Wikis: 'From Each According to His Knowledge'

Home , Knol, Socialtext, Ward Cunningham, Wiki, Wikiquote, WikiWikiWeb

COVER FEATURE Wikis: ‘From Each According to His Knowledge’

Daniel E. O’Leary University of Southern California

Wikis offer tremendous potential to capture knowledge from large groups of people, making tacit, hidden content explicit and widely available. They also efficiently connect those with information to those seeking it.

uch has been written about wikis in recent With wikis, multiple users can connect virtually in time years by researchers, journalists, blog- or space—from private communities within enterprises gers, and wiki software vendors. Not to the general public—to create, update, and share surprisingly, most of this information knowledge with others. appears in wikis themselves. Given the Wikis typically allow users to Mexplosive growth in wiki applications and the controversies surrounding the technology, it is useful to sort through the • add new content, claims and criticisms to better understand what wikis are, • link to other related content, how they are used, their advantages and limitations, and • edit existing content, various issues surrounding their implementation. • organize and structure content, • view content, and WHAT IS A WIKI? • access a history of contributed content. In 1994, Ward Cunningham implemented the first wiki, the WikiWikiWeb, to promote the exchange Most wiki contributions are written, but they can of ideas among fellow programmers on his consul- include media such as images, videos, and sound files. tancy’s website (http://en.wikipedia.org/wiki/Ward_ Web-based documents are created collaboratively in a Cunningham). Shown in Figure 1, the WikiWikiWeb simplified markup language, or “wikitext,” using a Web was written in Perl and based on a HyperCard stack browser over the Internet or an intranet. This enables Cunningham wrote in the late 1980s. Today, wiki soft- nonprogrammers to create wiki applications and add ware applications are based on numerous languages, new features without having to be familiar with the including Java, Lisp, PHP, Smalltalk, Python, and Ruby code base. (http://en.wikipedia.org/wiki/List_of_wiki_software). Wikis use various mechanisms to track the history of “Wiki” is Hawaiian for quick, and, as the term sug- contributed content so that users can see who made what gests, the technology’s initial goal was to give users the changes and when. Figure 2 provides an example of a ability to quickly put content on the Web. Today, how- wiki tool that compares versions of documents. ever, a wiki’s purpose depends on who you ask and what kind of application is being developed. In general, wikis Knowledge management are designed to facilitate quick and easy content Over the years, researchers have offered many propos- als to facilitate knowledge management, particularly at • generation, the enterprise level.1 However, the promise of various • collaboration, and tools and applications to make tacit knowledge explicit • distribution. remains largely unfulfilled—much tacit knowledge

Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. Figure 1. WikiWikiWeb. Ward Cunningham implemented the first wiki in 1994 to promote the exchange of ideas among fellow programmers on his consultancy’s website.

Figure 2. Wikibooks “history” interface. Wiki software allows for version comparisons of documents so that contributors can see who made what changes and when.

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. remains inaccessible. Wikis have the potential to gather tinually draw on a dynamic, ordered information set. The such knowledge from far-reaching sources. alternative is to “push” static, unordered information Wikis satisfy four key knowledge management directly to users, either individually or as a group. E-mail needs by represents the most common form of this approach.

• capturing knowledge from those who have it, WIKI APPLICATIONS • converting knowledge into an explicitly available A broad range of general and enterprise wiki applica- format, tions is in use today. • connecting those who want knowledge with those who have it, and General applications • linking knowledge to knowledge.2 The most well-known general wiki application is Wiki- pedia, the multilingual online encyclopedia that relies on In classic knowledge management, acquisition experts volunteers from around the world to contribute and edit are responsible for capturing knowledge from domain content on any given topic. Launched in January 2001 by experts. Wikis offer a nonintrusive means of capturing Jimmy Wales, it is one of the 10 most popular websites information by removing the intermediary and letting and currently contains more than 9 million articles in people share knowledge directly. 253 languages (http://en.wikipedia. Wikis also make information or Wikis all rely on the community org/wiki/Wikipedia). sources exclusively available to the The project’s tremendous success contributor generally available; at large rather than an elite spawned numerous siblings now users thus directly influence the group to advance knowledge, operated, along with Wikipedia, knowledge base’s structure and education, and discussion. by the nonprofit Wikimedia Foun- content. In addition, by making dation. These include Wiktionary, available information about con- a dictionary of term meanings, tributors, wikis facilitate connections between interested synonyms, etymologies, and translations; Wikibooks, a parties. Finally, through the use of hypertext, wikis let collection of open source textbooks and other learning contributors link appropriate knowledge. materials; Wikiquote, a compendium of quotations from prominent people and works; Wikisource, a library of Mass collaboration public domain texts and other source documents; Wiki- Wikis are particularly effective in situations in which media Commons, a repository of images, sounds, and a large group of people want to leverage their collective video; and Wikinews, a source for reports by citizen knowledge to achieve some goal. For example, during journalists. the 2004 US presidential contest, one campaign used Tens of thousands of independent wiki applications a wiki to compile political news stories for their candi- have sprung up on the Web to serve communities inter- date.3 This approach enabled some 400 staffers to focus ested in broad topics like computing, travel, and enter- on different areas of coverage—for example, around a tainment as well as niche subjects such as the online role- given periodical. The resulting database served as the playing game World of Warcraft. For example, Wikia, basis of twice-daily briefing documents. a for-profit company cofounded by Jimmy Wales, alone Within an enterprise, the choice of whether to imple- hosts more than 4,700 wiki communities (www.wikia. ment a wiki depends on the nature of the information com/wiki/About_Wikia). as well as the number of users. If a group wishes to keep Although some wikis impose restrictions on contribu- information private, then wikis, unless tightly limited, are tions, all rely on the community at large rather than an not appropriate as a means of fostering collaboration. elite group to advance knowledge, education, and discussion. The power of wikis to reach a broad constituency Transparency has not been lost on technology-minded political candi- To increase participation, content must be transpar- dates, who are beginning to incorporate them into their ent; otherwise, multiple participants will not be able to campaigns (http://vote.peteashdown.org/wiki/index. provide coherent and related contributions. Wikis pro- php/Main_Page). vide transparency by letting users see what others have contributed, thereby converting individual knowledge Enterprise applications into communal knowledge. Wikis have many applications within businesses and other organizations. Pull versus push Wikipedia imitations. The high visibility of Wikipedia Wikis facilitate the connection between those who has led many companies to replicate this type of applica- have information and those who need it. This “pull” tion internally.3 These internal wikis are typically designed mechanism is useful for organizations that want to con- to support particular functions by letting employees input

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. information as appropriate in an encyclopedia-like setting. For example, a WIKI ADVANTAGES business might employ a wiki-type • Wikis generate a network of knowledge by linking people and content product directory to record changes • Wikis can build consensus • Wikis collect knowledge from multiple sources and new offerings. • Wikis engage contributors Meeting setup. Wikis can help • Wikis can be as accurate as traditional published sources mitigate information overload.4 For • Wikis delegate control to contributors example, they can facilitate meetings • Wikis provide a forum to help users manage their behavior by gathering input in advance from WIKI LIMITATIONS attendees and making it generally • Wikis often do not provide author information, raising questions about content accuracy available. This saves time, particu- • Wikis typically lack referees or peer review, which provide some quality assurance larly in the case of multiday meetings • Wikis can hinder as well as build consensus, focusing on contributors’ conflicting opinions with much to assimilate, by enabling • Contributors can easily introduce bias participants to review what others • Wikis can compromise information security • Wikis can encourage scope creep have to contribute prior to the meet- • Contributions can decrease over time ing so that they can concentrate on • Wikis can expose an organization to legal problems areas that need attention. • Wikis are subject to vandalism Project management. Companies • Wikis can be contrived to look genuine but have an ulterior motive can use wikis to capture information • Wiki content is generally not available in a machine-processable format about projects. Participants can post documents and progress reports or Figure 3. Wikis have both advantages and limitations. generate and massage information related to a project on the wiki. For example, CommSe- the wiki’s capabilities to the desired objectives. Figure 3 cure, an Australian provider of e-billing and e-payment summarizes some of the pluses and minuses of wikis. solutions, employs a wiki to help track the implementation status and related documentation of different projects.5 Advantages This can facilitate buy-in by letting participants help con- Wikis offer numerous advantages. struct key inputs and making constraints transparent. Structure. At the highest level, wikis use a vocabulary Best practices. Employees can use wikis to describe or ontology to explicitly organize contributions. How- best practices. For example, the wiki “Library Success” ever, the use of hypertext to link related concepts and is a “one-stop shop for great ideas and information articles within the wiki embeds additional structure. for all types of librarians” (www.libsuccess.org/index. Some wikis, such as Wikipedia, also contain references php?title=Main_Page). Another wiki’s expressed goal is and external links to other subjects. to share best practices about the Common Base Event, a Consensus. Wikis can build consensus because many fundamental systems management standard (www.ibm. participants often “sign off” on the content. In fact, com/developerworks/wikis/display/CBEbestpractice). building consensus is Wikipedia’s “fundamental model Taxonomy development. Wikis can simplify taxon- for editorial decision-making” (http://en.wikipedia.org/ omy development within an enterprise, which generally wiki/Wikipedia:Consensus). Wikis typically encourage requires the cooperation of multiple parties. Individual a neutral point of view and have mechanisms to resolve users can propose a portion of the taxonomy and its disputes among contributors. associated explanation, and others can point out their Collective wisdom. Because wikis are generally open, limitations and suggest changes. democratic environments, they harness the “wisdom of Competitive intelligence. Wikis can be used to the crowd.” Ideally, content draws on a wide range of gather competitive intelligence, a function traditionally contributors with varying perspectives and expertise. performed by a small group within the organization that Everyone in the community has an opportunity to evalu- acts in relative secrecy. SAP, one of the world’s largest ate the quality of contributions, and those who have an business software companies, employs a wiki to monitor interest in or are knowledgeable about a topic can add to how its pricing tactics and sales strategies are working in or modify content. the field.3 By making the process open and participatory, User engagement. Wikis engage users by letting them the company can get better and more timely collective express themselves freely and for all to see. Although intelligence and make it available to more people. most wikis have etiquette guidelines and codes of con- duct prohibiting, for example, hateful content or per- WIKI ADVANTAGES AND LIMITATIONS sonal attacks, individuals generally have tremendous In determining whether to implement a wiki, an enter- flexibility in what they post. Users derive satisfaction prise or other organization must balance the advantages from being part of a communal effort as well as seeing of the technology with its limitations as well as match their creativity on display.

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. Accuracy. Contrary to the claims of some critics, wiki the wiki. For example, Microsoft purposely separates accuracy can be comparable to published sources. For product and market information, and users able to inter- example, one recent study found that Wikipedia had mingle data through a wiki could gain deep insights into roughly four inaccuracies per entry, only one more than the company’s revenue stream.9 Encyclopedia Britannica.6 Some wikis have verifiabil- Scope creep. Because wiki contributors can range ity guidelines that encourage contributors to cite reliable from amateurs to professionals, from beginners to sources. experts, the resulting content might be too amorphous Delegation of control. Wikis delegate control of con- to be of use to any particular group. Scope creep is a tent to potential contributors. This is an advantage in common problem on complex projects, and wikis can organizations where management seeks bottom-up input encourage it by facilitating changes in team composi- on particular issues or processes. tion. User management. Wikis can help manage users as Decreased contributions. Wikis, particularly discre- well as contributors by providing widespread access to tionary ones, can suffer a slow death. In some cases, con- equivalent standards for actions and behaviors, whether tributions are initially heavy but subsequently decrease implicitly or explicitly. as participants turn to other activities. In other cases, contributions are light to begin with, increase as users Wiki limitations familiarize themselves with the technology, and then Wikis also have several limitations. decline as the uniqueness of the technology wears off. Lack of authority. Users might want assurance that Unfortunately, both scenarios result in a similar out- material they obtain online is backed by some authority come: decreased contributions over time. or level of expertise. Unfortunately, in many cases there Legal problems. Enterprise applications such as is limited information about authors of wiki material. For project management rely on contributors being frank example, a Wikibooks contributor named “Psychofarm” and honest, but openness in company e-mail has led has written books on both Mac OS and Asian honey to expensive lawsuits—even in instances with only chicken salad, while another has offered works on both one recipient of a message. It is easy to imagine how a physics and accounting. Such broad interests naturally wiki could, by disseminating sensitive or private data to raise doubts as to whether these authors have the neces- numerous people, expose an organization to all sorts of sary expertise. legal problems. No referees. Few wikis referee content to any appre- Vandalism. Wikis are only as good as their contribu- ciable extent, if at all, because that violates the open wiki tors, and these can include users who submit obscenities, spirit. Consequently, there is no guarantee that informa- personal attacks, and deliberate nonsense. Vandalism tion in wikis is accurate or even reasonable. Wikipedia, has actually forced some organizations to cancel wiki for example, has had well-documented problems with applications. For example, the Los Angeles Times closed users submitting invalid information.7 In contrast, pub- down its “Wikitorial” feature because of contributors’ lished research is typically peer-reviewed and edited, repeated use of foul language.10 providing some quality assurance. Contrived wikis. Because wikis facilitate consensus, “Too many cooks in the kitchen.” Wikis can hinder as some use them to try to generate consensus within an well as build consensus. If multiple contributors express enterprise or the general public. Contrived wikis are conflicting points of view or alternative solutions, the implemented by some anonymous source to look like a resulting content might be incoherent or focus on differ- standard wiki, with open contributions, but are actually ences rather than similarities. Wikis can also mislead- not open and designed to influence public opinion. ingly give the appearance of consensus if only one or a Human consumption. In general, wikis are generated small group of contributors dominate the process early by and for humans. However, many knowledge manage- on, thereby thwarting further discussion. ment systems, such as rule-based systems, attempt to Bias. Although many wikis have policies advocating put information in a machine-consumable format, inter- a neutral point of view, their open nature makes it easy mediary to human consumption. Such machine-based to introduce biased information. For example, a former consumption is generally beyond the scope of wikis. MTV veejay and podcasting pioneer was caught anony- mously editing the Wikipedia entry on podcasting to IMPLEMENTING WIKIS take credit for its development away from others and Some organizations that implement a wiki might inflate his own role.8 expect to simply “build it and they will come” (and use Information insecurity. Wikis can compromise infor- it). However, the open nature of wikis raises several mation security. Organizations often compartmentalize issues that are often ignored. data, giving different pieces of information to different Author information. Enterprise wikis usually keep users, but wiki users could inadvertently share data data about wiki authors. As Figure 4a shows, captur- that should not be available to all who have access to ing such information can be critical to achieving user

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. (a)

(b)

Figure 4. SAP wiki. (a) Capturing author information can be critical to achieving user acceptance of content. (b) Issuing “points” with associated benefits to employees for their efforts encourages participation. acceptance of content. It can also foster connections Wikipedia, no one person or even group can monitor between users and authors. Google recognizes this and all of the changes in real time. is implementing its own competitor to Wikipedia, Knol, Change alerts. One way to provide control over that prominently displays authors’ names (http://blogo- changes is to alert those who have indicated inter- scoped.com/archive/2007-12-14-n19.html). est in a particular subject or whose previous con- Incentives to participate. Wikis should provide tribution has been altered by another user. Par- potential contributors with incentives to partici- ticipants who know that changes they make to pate. As Figure 4b shows, one way to do this within existing content will be broadcast to the original an enterprise is to issue “points” to employees, with author will likely be more discriminating, while some reward upon reaching a certain threshold, for those whose contributions have been edited will their efforts. In addition to displaying authors’ names, have a chance to quickly review the changes for Google’s Knol will let authors include advertisements inaccuracies or other issues. and make money from their contributions. Access and registration. The original philosophy of Administration. Ideally, wikis should have an wikis was to let all users contribute and change content. administrator who referees and manages the changing However, such openness can lead to vandalism, tamper- content. However, if the wiki is substantial, such as ing, compromised data, and other problems, particularly

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. in noncorporate settings where there is little recourse for ful. For example, Wikibooks indicates whether text for destructive acts. any given project is “sparse” (0 percent), “developing” In corporate environments, it is important to deter- (25 percent), “maturing” (50 percent), “developed” (75 mine whether wiki access should be open to outsiders percent), or “comprehensive” (100 percent). Because or limited to employees, managers, or a select group of there are likely to be multiple contributors, and com- users within the company. Does the wiki contain infor- pleteness is in the eye of the beholder, estimates can be mation—for example, about product faults—or con- highly subjective. troversial content that, if made available to the wrong Design for participation. Because wikis depend on people, could negatively impact sales, compromise pro- contributors, any implementation should be designed prietary secrets, or lead to costly litigation? to facilitate participation. Ross Mayfield, cofounder of Perhaps the least intrusive way to control access is Socialtext, the leading enterprise wiki company, sug- to notify potential contributors that their IP address is gests starting small with a pilot project that applies a being captured. Another method is to require that users wiki solution to a single process or application.3 Once register with a valid e-mail address and log in with a the project participants have evaluated the tool through username and password. Although the effectiveness of a forum or discussion group, they can “take it public” these steps can be mitigated, they at by each inviting five others in the least provide some potential control organization to use the wiki. This over users. Researchers have used wikis can be repeated with successively Contributor capabilities. One to generate and maintain larger waves of contributors, gradu- way to manage users is to categorize ontologies and taxonomies. ally building a community, adding them according to their capabilities. content, and evolving norms. Wikibooks distinguishes contributors Personalization. Many wiki according to their fluency in English and other languages. applications let users personalize some aspects such For example, User en-N connotes a native English speaker, as privacy settings, link formats, image size, editing while User en-0, -1, -2, and -3 represent users with zero, options, browser appearances, date format, and time basic, intermediate, and advanced levels of English, respec- zone. tively. To limit wiki access in enterprise settings, contributors can be assigned “roles” based on their responsibilities EMERGING AI APPLICATIONS IN WIKIS or level of expertise. In simple terms, artificial intelligence aims to incor- User practice. Although most wikis are relatively sim- porate human intelligence into computer-based applica- ple, they can be intimidating to first-time users. Many tions or analysis. There are numerous potential applica- sites therefore provide a “sandbox” that lets contributors tions of AI in the area of wikis. learn the wiki’s various features and practice, thereby Wikis provide substantial structured material about limiting potential mistakes. Sandboxes might also facili- particular subjects, and researchers have used them to tate user buy-in. generate and maintain ontologies11 and taxonomies.12 Policies and guidelines. Wiki contributors should Similarly, group input could be used in a wiki to gen- clearly understand what they can and cannot do. The site erate rule-based knowledge to capture insights and should therefore offer a list of mandatory policies and identify conceptual relationships. Systems designed advisory guidelines, subject to community approval. For to improve knowledge by intelligent questioning and example, Wikipedia users must respect other contribu- answering could also leverage wiki content. tors, respect copyrights, avoid bias, and include only Just as electronic auction sites generate reliability or verifiable information (http://en.wikipedia.org/wiki/ quality estimates about buyers and sellers, AI systems Wikipedia:Key_policies_and_guidelines). could search the Internet and other wikis to find out Copyrighted material. In many settings, wiki-based what particular authors have contributed on various top- materials cannot be copyrighted. For example, Wiki- ics and generate trust or expertise indices. Researchers books considers all contributions to fall under the terms also could develop intelligent agents to search multiple of the GNU Free Documentation License (http://www. wikis and assemble material for a comprehensive article gnu.org/licenses/fdl.html). Wikibooks warns potential on a subject. violators that “the posting of copyrighted material with- Wikis such as Wikipedia address the same topics in out the express permission of the copyright holder(s) is numerous languages. Researchers could use this multilin- possibly illegal and is a violation of our copyright policy” gual data to disambiguate topics, terms, or words; gener- (http://en.wikibooks.org/wiki/Wikibooks:Copyrights). ate translations; or analyze structure in a subject area. Project completion estimates. Although wikis are Researchers also could use AI systems to help secure typically open ended, some projects can have a com- wikis, whose open nature makes them particularly vul- pleted format. In these cases, providing users with an nerable. For example, concept-based systems could iden- estimate of how much work has been done can be help- tify vandalism and exclude such contributions prior to

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Authorized licensed use limited to: IEEE Xplore. Downloaded on January 1, 2009 at 11:48 from IEEE Xplore. Restrictions apply. posting, while intrusion-detection systems could lever- 10. P. Naughton, “Foul Language Forces LA Times to Pull the age information gathered about contributors to unmask Plug on ‘Wikitorial,’” Times Online, 21 June 2005; http:// illegitimate users. technology.timesonline.co.uk/tol/news/tech_and_web/arti- Wikis can be used as a training ground to search cle535749.ece. for knowledge obtained through machine-learning 11. M. Hepp, D. Bachlechner, and K. Siorpaes, “OntoWiki: Com- approaches. Further, annotating wikis with machine- munity-Driven Ontology Engineering and Ontology Usage readable content would make them both human and Based on Wikis,” Proc. 2006 Int’l Symp. Wikis, ACM Press, machine-friendly. 2006, pp. 143-144; www.heppnetz.de/files/ontowikiDemo- short-camera-ready.pdf. 12. A.L. Burrow, “Negotiating Access within Wiki: A System to ikis offer tremendous potential to capture knowl- Construct and Maintain a Taxonomy of Access Rules,” Proc. edge from large groups of people, making tacit, 15th ACM Conf. Hypertext and Hypermedia, ACM Press, W hidden content explicit and widely available. 2004, pp. 77-86. They also efficiently connect those with information to those seeking it: “from each according to his knowl- Daniel E. O’Leary is a professor in the Marshall School edge, to each according to his need.” Although wikis of Business at the University of Southern California. His have inherent limitations that make them inappropri- research focuses on information systems, including enter- ate in certain settings and for some applications, they prise resource planning systems and knowledge manage- are likely to replace existing processes and technologies, ment systems. O’Leary received a PhD in information sys- providing organizations with a wide range of additional tems and systems engineering from Case Western Reserve capabilities. ■ University. He is a member of the IEEE, the ACM, the Institute for Operations Research and the Management Sciences, and the Decision Sciences Institute. Contact him Acknowledgment at [email protected]. The author thanks the anonymous referees for their comments on an earlier version and extends apprecia- tion to the editors for their efforts to help make this a better article. Giving You the Edge References IT Professional magazine 1. D.E. O’Leary, “Enterprise Knowledge Management,” Com- gives builders and managers of puter, Mar. 1998, pp. 54-61. enterprise systems the “how to” and 2. D.E. O’Leary, “Knowledge-Management Systems: Convert- “what for” articles at your finger- ing and Connecting,” IEEE Intelligent Systems, May/June tips, so you can delve into and fully 1998, pp. 30-33. understand issues surrounding: 3. R. Mayfield, “How to Start a Wiki;” podcast, www.veotag. com/player/?u=rivtyskosd. • Enterprise architecture 4. J. Spira, “Information Overload—A Growing Problem,” and standards Collaboration Loop, 1 Feb. 2007; www.collaborationloop. • Information systems com/index.php?option=com_content&task=view&id=1945 • Network management &Itemid=39. 5. L. Wood, “Blogs & Wikis: Technologies for Enterprise Appli- • Programming languages cations?,” The Gilbane Report, Mar. 2005, pp. 2-9; http:// • Project management gilbane.com/artpdf/GR12.10.pdf. • Training and education 6. J. Giles, “Internet Encyclopedias Go Head to Head,” Nature, 15 Dec. 2005, pp. 900-901. • Web systems 7. D. Terdiman, “Growing Pains for Wikipedia,” CNET News. • Wireless applications com, 5 Dec. 2005; http://news.com.com/Growing%20pains% • And much, much more … 20for%20Wikipedia/2100-1025_3-5981119.html?tag=st.prev. 8. R. Cadenhead, “Adam Curry Caught in Sticky Wiki,” Workbench, 1 Dec. 2005; www.cadenhead.org/workbench/ news/2818/adam-curry-caught-sticky-wiki. 9. D.E. O’Leary and M.L. Markus, “Microsoft’s Management Reporting: SAP, Data Warehousing, and Reporting Tools,” J. www.computer.org/itpro Emerging Technologies, vol. 3, no. 1, 2006, pp. 129-141.

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