Proceedings of the First International Congress on Construction History, Madrid, 20th-24th January 2003, ed. S. Huerta, Madrid: I. Juan de Herrera, SEdHC, ETSAM, A. E. Benvenuto, COAM, F. Dragados, 2003.

A hypothesis on a building technique to determine the shape of the Nuragic tholoi

Serena Noemi Cappai

The countryside and culture of are The notable architectural development was made characterised by the presence of Nuraghi, an possible by the nature of Sardinian surface rocks, architectural expression of the Nuragic Civilisation such as basalt, trachite and granite, with good (2000-500 B.C.). building potentiaI.2 The expression «»I is used for two The single tower tholos nuraghe, the subject of my different architectural types, corridor nuraghi and study, is from the outside a circular based tower with tholos nuraghi. a truncated conical profile, built in the drystone The first type has a tlat ceiling corridor which runs method, i.e. without any form of cement, and with a through the whole structure, and slopes towards the complex arrangement of internal spaces. top thanks to overhanging blocks. The planimetry is The inclination of the externa] walls is produced by irregular, subquadrangular or elliptical and is only the position of the stone blocks which are sited one rarely circular. above the other is a horizontal order. Two different Whereas a tholos nuraghe has one or more circular stone dressings can be easily distinguished in the based chambers, one above the other. Their form is external walls. The lower Ievels were made of that of a tholos or falsacupola. This has been defined cyclopic stone, with the blocks of polygonal stone as a «classic nuraghe», both because of its numerous roughly cut, laid in horizontal circles and infilled with presence in the island and because ofits «elementary» smaller stones to leve] the next layer. The higher building technique i.e. a truncated conical tower, with layers are of smaller size and have a wedge or quoin successive additions of walls and angular towers shape which aIlow an increased regu]arity of the producing the socaJled Complex Nuraghi with horizontal layers. These higher levels are therefore labyrinthine planimetry e.g di , S. more regular and more easily distinguished. The Antine di Torralba and the five-tower Nuraghe section of the construction is hoIlow-wall, that is, Arrubiu di . made of two walls between which there is a space Nuragic builders designed and built, apart from the which has been filIed with rubble of different sizes. nuraghi other architectural structures, of a sacred The two wall are joined by stone slabs positioned character such as fountains and holy wells and transversely and sunk into them to function as «Giants'Tombs» (collective graves), all with their reinforcement. own uses, but all with a single building technique i.e. Single tower nuraghi had originalIy at least two an overhanging wall construction (evolution of the chambers, one above the other, the entrance to which trilithic system). was from the stair which, according to the slope, 536 S. N. Cappai could reach the floor above with a half or full turn, single element takes part in the stability of the whole. always clockwise, until it reached the summit of the Studies so far undertaken into the building techniques tower where originally there was a terrace.3 of the nuraghi have been interested in the methods of The interwall staircase is an ever present element transport and positioning of the enormous blocks of within the nuraghi, and two building techniques can stone needed for their construction. be found in the thousands of towers «scala di The realisation of a work such as a nuraghe was a camera» and «scala d'andito». rather complex operation, requiring a notable use of The first type begins from the main chamber and at resources and human energy as well as a functional a certain height from the ground (for example at organisation of the building site. Given the number of Nuraghe Is Paras-Isili it begins at a height of 5.50 towers built it is reasonable to think that the building metres) and passing between the walls reaches the technique was the patrimony of the Sardinian people. next floor. In most of these types of nuraghi, the base They probably had on hand a clear building project, chamber is centrally placed in relation to the external knew, possibly empirically, the caracteristics of their diameter of the building and the thickness of the walls materials, and above all knew exactly, given their is insufficient to support the beginning of the staircase experience, which were the critical points of the at this height. In fact the incline of the chamber wall sructure. In fact we find throughout the territory the determines, at a certain height from the ground, the same structural scheme, at least in its essentials. height sufficient for the passage of the staircase. We can imagine the coordinated work of a number The «scala d' andito» is, on the other hand, of teams who undertook the choice, cutting and technically more advanced and probabily more laying of the blocks. Machinery was used for raising recent, because its construction presupposed a greater the blocks. In fact a deliberately carved stone was design ability compared to the previous one due to found near Nuraghe S. Cristina di , which control of the whole elicoidal development of the was probably used as a counterweight on the building interwall staircase and the subsequent positioning of site.4 the upper chambers. The staircase has, in fact, a route The first phase of the construction was establishing from ground level to the top of the tower with spaces the building plan and therefore the organisation of the only for the entrance to the upper chambers. The internal space of the tower and architectural choices circumference of the ground floor chamber is not such as the type of staircase, which as we have seen, concentric to the external circumference of the tower determines and defines the details of the upper t10ors. which means in section, the eccentricity of the As the construction rose, level by leve\,5 spaces were chambers with regard to a vertical axis sited at the defined, full and open, which defined the final centre of the external circumference. structure. The critical points were the open spaces such as openings, niches and especially the route of the intermural staircases. In the upper levels the BUILDING TECHNIQUE external walls reduce in thickness (from medium at the base of 4 metres to a medium of 1.5 metres in the At the beginning of the construction of a complex and upper layers). This was due to both to the more articulated building such as a nuraghe there is a plan, regularly cut stones used at this level to the more a theoretical and methodological formulation, which regulary levels of the layers, and to the inclination of permits control of its completion. Building is not the external wall. based on improvisation or spontaneous invention, but The tholos, the system of covering the nuragic must be the result of the fusion of construction and chamber, is created in dry stone concentric rings laid project. It would be wrong, in fact, to consider the act on above the other horizontallt. Every successive ring of building and planning as casual. Planning and is positioned inward with respect to the lower one in construction run side by side and are the result of the order to produce a vertical section with a curved consolidation of acquired experience and building profile. As the building rises the blocks are smaller practice. A nuraghe was a construction in which and the roof ends with the smallest blocks which are structure and functionality were integrated, and there them selves closed with a cap stone. The resultant self are no superfluous or secondary elements, every supporting structure is capable of remaining standing A hypothesis on a building technique to detennine the shape of the Nuragic tholoi 537 during construction without the help of any system of centring. The thoJos is a revolving structure which has in fact both horizontaJ circular section and vertical symetrical section in relation to an axis which coicides with the perpendicular at ground leve! which pass through the apex. The volume determined by this structure is obtained by the rotation around the axis of Asta symetry of the profile of the intrados. A structure geometrically defined in this way cannot be realised without the help of a building method capable of controlling its horizontal development, vertically and radiall y. The aspect of the building technique on which this study concentrates is the discovery of a method, simple and efficient, for the determination and control in the building stage, of the archway soffit (intrados) of the tholos. A building method to create an overhanging roof Figure] with the form of a nuragic roof has been proposed by Method proposed by Cavanagh and Laxton for the detennination of the curvature of the tholos two English scholars W. G. Cavanagh and R. R. Laxton6 who believe, after having studied 15 nuragic tholoi, that simple instruments such as treetrunks, sticks and ropes would suffice to check the curvature of the chamber as construction goes ahead. The uses simple tools such as trunks, ropes and a method7 (Fig. J) which they propose consists of siting plumbline. a trunk of height equal to H units (one unit equaJs haJf The first construction phase of a nuraghe consists of the layer height) at the centre of the chamber in a of establishing in plan the internal spacial vertical position, place a wooden beam perpendicular organisation of the first leve!. Thus the external to the trunck on the last layer built, tie a rope to the dimension of the tower, and the position of the top of the trunk and move it as far as the upper edge chamber and its diameter are established. Having inside the last complete layer. completed the first Jayer of stones (Fig. 2) a trunk of Then one runs horizontally on the wooden beam a height H slightly inferior to the real height of the roof stick of two units of height, marked at the middJe, is sited in the centre of the chamber in a vertical untiJ the rope passes this point, the next level must be position. positioned until it touches the stick. The same At the top of the pole is fixed a rope of a length manouvre is repeated until the roof is closed. egual to the distance from the point at the top of the This hypothesis, though based on the use of simple pole to the upper internal edge of the first ¡ayer, plus tools, is from the constructional point of view the height of the layer itself. complicated and restrictive. In fact the method as At the bottom end of the rope a weight is attached proposed is applicabJe only to the tholoi which have producing a plumbline. a constant height of layers. Also, if the technique The overhang of the levels is determined thus: the were used to construct a nuragic tholos with layers of rope is stretched from the top of the pole as far as the a decreasing height from below to above, it would be upper internal edge of the stone aJready laid, then the necessary to have a different stick for each height of stone is moved until the weight at the end of the rope layer, making the method even more compJex. touches the ground. The same operation can be The present work, as an aJternative to that of undertaken radially as many times as is necessary to Cavanagh and Laxton for the control of the curvature position the various stones of the same ¡ayer. The of the tholos is based on a building technique which process then continues layer by Jayer (Fig. 3). 538 S. N. Cappai

To better understand the chracteristics of the construction and the hypothesis proposed it is better to observe the geometrc properties of this conic. The parabola is the geometric locus of the points on the plane equidistant from a fixed point called the Focus and from a straight line called the Directrix. It is also possible to define the parabola as a Limit Ellipse, and therefore as the geometric 10cus of the points on the p1ane for which the sum of the distances from two fixed points called Focus which is constant and belongs to the axis of symmetry and of which one to infinity. (Fig. 4) To verify whether the curve obtained by sectioning the nuragic tholos vertically through its axis is a Figure 2 parabola, the data obtained by Cavanagh and Laxton Description of the building method on a sample of pseudovolts were used. Among the data published the following sections of nuragic tholoi were closen, Is Paras-Isili, Palmavera-A1ghero, S. Sabina-Silanus, the first and second chambers of S. Antine-Torralba and Orolio- Silanus. For each tholos the two scholars provide the coordinates of the points found during the measurement, referring to a Cartesian system beginning at the top of the tholos. Having considered the generic function of the parabola y = -ax2 (the negative sign indicates the concavity of the curve downwards) and notes x y coordinates of the points in the tholos, the coefficient to determine the function of every single section remains unknown. Assigning to x and respectively the values of the Figure 3 radius (regarding the axis of the tholos) and of the depht (regarding the apex) of a point chosen, based on the most probable parabolic a1ignment of the points, the coeff¡cient of the parabola can be found. With this method it is possible to check the circular For a generic point P we therefore have and xl' Yl' nature of the horizontallayers and to establish that as and from the equation the tholos is built, the growth of the whole building is yp controlled horizontally. In this way the part a1ready =-ax~ we obtain the coefficient a = - 4.x- I' built becomes the base upon which the builders could At this point it is possib1e to obtain the function of work and control the who1e internal spacia1 the parabola with the data of Cavanagh and Laxton. organisation which otherwise wou1d be too difficu1t Such comparisons (Figs. 6, 7, 8, 9, 10, 11, 12) and in to manage. particular the one re1ative to the figures of Nuraghe S. Sabina-Silanus would confirm the validity of my hypothesis.8 THE GEOMETRIC CHARACTERISTlCS OF THE CURVE The tholos is therefore a structure with a geometry which is also a building rule. The curve obtained with this building method is a In order to relate the equation of the parabola y parabola and the volume of the tholos is a paraboloid. = -a:x2 to the building method pro po sed it is necessari A hypothesis on a building technique to detennine Ihe shape of the Nuragic tholoi 539

y F]A + AF2 =K

DIREITRICE F]C + CF2 =K

x then

BF2 = 00 = K' 00 DF2 = = K'

and still

] BF F A + AF 2 - 2 =K - K'= K" K11 F,C + CF2 - DF2 = K - K' = y= -aX2 so

F]A +ABK" '_'_0_0 F ]C + CD KII

}200

Figure 4

to specify the dimensional parameters which more advantageous, with equal heightand diameter, a determine the coefficient. This defines the form of the parabolic rather than a conical profiJe, because of the parabola, as a with p equal to the distance greater saving in material and the subsequent load = ~p reduction. between the Focus and the Diretrix; in the proposed Furthermore, at equal height, more space vertically method the top of the pole represents the Focus, and is obtained, and so there is the chance to have, the parameter p of the parabola the difference through the use of wooden platforms, more useflll between the lenght of the rope and the height of the space. pole. To determine the Focus geometrically it is In fact these building s are in a poor state of sufficient to prolung a tangent to the curve until it conservation. Often the tholos are withollt their upper intersects the axis of the x and trace a perpendicular levels incomplete. To hypothesis the original height from this point to the tangent line until it intersects the cOllld be important, therefore, in vallling the history axis of y. This defines the height of the pole which is of this architecture if we accept the hypothesis so far equal to the height of the chamber subtracted from the given as valid, we can have a means of defining the distance Focus- Vertex. height of the tholos which are reduced to the state of The length of the rope is equal to the sum of the ruins.a double distance Focus- Vertex plus the height of the After having lIndertaken an accurate survey of the poleo The choise ofthe profile to give to the chambers remains of the tholos, the measurements are put into of the nuraghi is the result of a spacial optimization a Cartesian system, and YOll draw the curve which aimed at reducing the full-empty relationship. passes throllgh the points which show the most To endose a space with a circular base it is held probable alignment. 540 S. N. Cappai

Definided as B and e, respectively the lowest and [1] highest of the curve, we assume XB and Xc as radii of the tholos with respect to B and C. Given the implicit YB-YC='a(x~) equation of the parabola y -ax2 and the Cartesian =' and that coordinates of points B and C, it is necesary to find h, the value of the coefficient a to determine the YB - Yc =' equation of the parabola which passes through the points of most probable alignment. la [1] becomes: The equation for the required parabola has a X2) and so a h h a (- X2B + B . coefficient negative and does not show the constant =' =' (x~ - x~) so the conic has a vertex at its origin and concavity towards the ground. Once the coefficient of the parabola has been found, the hypothetical height of the tholos can be found by inserting the values of a and X, radius of the base of the y tholos, into the generic function of the parabola. Theoretically this method is valid for the tholos which are no longer complete, which preserve a residual height of at least 3 metres and a noteable beginning to the curve. The precision of the result x obtained is linked to the regularity of the section and the reliability of the survey. The hypothesis of the building method so far formulated helps us to understand the building -. .-.-.-.-. technique and the geometry of nuragic tholoi,9 and therefore allowus to describe theirspacial configuration Xc and structure. This is the starting point towards the definition of a I~ geometric model before an structural analysis of the tholoi, a subject at the moment under study. The necessity to investigate and understand the I dynamic of the whole construction is dictated by the . conviction that in order to preserve the historical Figure5 testimony an adeguate technical-structural knowledge is necessary. At the moment the nuraghi (but this applies also to other nuragic construction such as a sacred Wells and In this Cartesian system (Fig. 5) we note in the Giants'tombs) are in a very poor state, caused by the but the passage of time and because of attemps at curve surveyed the coordinates XB and XC' ordinates are obviously unknown. Of the ordinates YB consolidation of an irreversible nature used until now. and Yc it is however noted their difference which is Unfortunately the use of modem materials such as equal to the distanceon the between B and C. cement, metal bars and resins introduced via perforation cause permanent damage to the monument. If 'The work so far undertaken has not been done to resolve forever the problems inherent in the -ax2 and -ax~ YB =' Yc =' construction technique originally used, but should be seen as a first step towards an understanding of the then structure, in order to make interventions possible (-ax¿); which are less destructive which will allow a better YB- Yc =' -ax~ - preservation of these witnesses of our past. A hypothesis on a bui1ding technique to determine the shape of the Nuragic tholoi 541

Nuro.ghe S,So.blno. curvatura. tholos CQ.Mero. Nuro.ghe 15 Po.ro.s curvatura. thalos Co.Mero. r-;-l Puntl ,..IL",vc.1;1eje. ~CQVQnQQh-LQxton ~ ~~8~~~~~~~:~tdonn Curvatura Curvatura r\I aeterl'llna.-ta ¡:on 1\ ¡:on 1\ L.lJ Metodo CJ ~:~~~~lnQtQ c:ostruttlvD Dlrettrlce ccstruttlvo Dlrettrlce propos1;o proposto

X..=2,52 X,.:=3.20 Yp::-5,96 Y..=-7.BO

Figura 8 Curvature of the tholos in the Nuraghe S. Sabina-Silanus

Figure 6 Nuro.ghe S,Antlne 1 co.Mero. Curvature of the tholos in the Nuraghe Is Paras-[sijj r-;I Puntl rlleva. ti da L...:...J Cavo.nQ.gh-Lo.xton Curvc.turo. r':"l deterr'llnc.tCl. con 11 L...:::.-.Il"letoclo costruttlve propostc Dlrettrlce

Nuro.ghe Po.lr'Hlvero. curvo.turo. tholos Co.Mero. ~Pun.tlrllevQi;ldQ L : JCavo.nagh-Lc.x1;on X.=2.52 Curvatura Y,.=-5.96 detE'r'",lnc.to. con 1I ~n[]5tr[]I'It?-todD1"';"""1 Diret-trice costr\.ol-t1;lvD

X.=2.32 Yp::-4,20

..

Figure9 Figura 7 Curvature of the tholos in the first chamber of the Nuraghe Curvature of the tholos in the Nuraghe Palmavera- S. Antine-Torralba 542 S. N. Cappai

Nuro.ghe Drollo CUrvO.tura tholos r co.Mero Nuraghe Oro ID curvo. ura.

r-;-l Puntl rllevati do. 8 ~~~¿~~~~~~:~tao~ L.:...J Cavanagh-Lllxton CurVc.1;Uro. Curvo. turn to. con Il cleterrollno.-to. con 11 [TI ~:i~~~'no. LUl'\etoc:lo~ costruttlvo c:05truttlvo proposto DlrettrlcE' propcsto

'.

Figure 12 Figure 10 Curvature of the tholos in the second ehamber of the Curvature of the tholos in the seeond chamber of the Nuraghe Orolio-Silanus Nuraghe S. Antine-Torralba

Nuro.ghe S,Antlne II CaMero. NOTES Puntl rllevo.-tlao. ~ Co.vo.no.gh~LD.xton L:--1 Curvatura. This work is part of my graduating thesis written and r-I aeterl'llno.to. con 11 ~ Metodo presented at the Faeolta di Arehitettura di Firenze (a.a. c:ostryttlvo proposto Dlre trlce 1999-2000), together with the eollegue and friend Areh. Giuseppe Pulina to whom goes my gratitude. O,74X2 . y"" '-$'-.:"" Furthermore I would like to thank the Fondazione del

'<}' ~ Banco di Sardegna that made possibile my researeh

" !'''~,~" I work «Torri nuragiehe: caratteristiche tecnico- ~"','1 iP ' ' strutturali»; Prof. Luciano Barbi of the fae. Architettura r' '* ., ¡lO di Firenze. Prof. Barbara De Nieolo of the Fae. I " ,! i, Ingegneria di for the preeious suggestions and ,,. , , ," the constant support, and last but not least David Bollart , ", ." for the eare had in translating this work. , I, . ~~ \2-'" l. The expression «Nuraghe» comes from the word «nurra» whieh in the Sardinian dialect means «heap» or «eavita» and so a hollow construetion. Nuraghi are mentioned in classical literature by the Greeks as Figure 11 deda/ei and th%s and by the Romans as castra Curvature of the tholos in the first ehamber of the N uraghe (castles) and spe/onche. Orolio-Silanus 2. If, in faet,we observe the geol ithological map of Sardinia compared to the density of nuraghi it is evident that, in the flat lands and alluvial plin these areheteetural outerops beeome rarer until they disappear all together. The explanation can be found in the faet that building became more difficult in those areas in which the most suitable lithoid material was ot immediately available on the surface. 3. Originally a nuraghe had an over hanging parapet built A hypothesis on a building lechnique to detennine the shape 01'the Nuragic tholoi 543

into its highest level, resting on alternative corbels and and R. R. Laxton «An investigation into the costruction stonc blocks and forming an integral part 01' the 01' Sardinian Nuraghi», 1987. underlying wal1. The discovery in the piles 01' stone 8. The discrepancy 1'ound in the alignment between the caused by col1apse, found at the base 01' several towers curve determined according to my hypothesis and the cut in corbel shape, and the finding 01'models 01'nuraghi points discovered by Cavanagh and Laxton, are due to showing this type 01' roof would confirm this type 01' the summary working 01' the visible faces 01' the stone overhang used to sustain an open terrace. blocks, as the profile 01' the intrados is not regular. Not 4. The use 01' wood, not only in the building stage but also only, but the survey undertaken by measuring the rays within the finished nuraghi, has been found in some at a constant but too short distance do not take into nuraghi in the form 01' internal-wal1 holes for the consideration the horizontal flights 01' the layers positioning 01' wooden roof-beams. Nuraghe Oes- produces the error. , a nuraghe with two external towers with a «scala 9. The principIe on which the construction 01' nuragic d' adito» i this respect is 01'particular interest. lts interior tholoi is based, as we have seen, is the progressive is an open cylinder, original1y covered by a single overhanging 01' the stone blocks. The same criteria can tholos. This environment was probably divided be found in the other types 01'architectural construction vertical1y by wooden garrets, resting on continuous built by the Nuragic peolple, in the hypogeic tholoi 01' horizontal stone ledges, one for each floor, joined by an the holyweels, in the system 01' c10sure 01' the corridors interwal1 staircase 01' an elicoidal shape.this is a very 01'the bastion in Complex nuraghi, as al so in the single refined solution 01' spacial use because thc chambers corrido 01' the Giants' Tomb. TI is also possible the preserve more or less the same size and do not diminish hypothesise in these last two cases the use 01'the method in diameter with height. Energy is also saved by used for the tholos, with the difference that, in the case avoiding the construction 01'a tholos for every chamber. 01' the corridors, there is a translation 01' the parabola 5. The Nuraghe Ruggiu- (Fig.), a single tower along a horizontal axis and not radial1y as happens in with tholos and «scala d'andito» has inits interior al the tholoi. This subject is at the moment being studied. level 01' the passage entrance, stone slabs between the outer wal1s 01' the tower and the inner wal1s 01' the tholos. sunk. therefore, into the two parameters 01' the REFERENCE LIST nuraghe. This particular feature, which can be found also in other cases, bears witness to the fact that the Bernardini, Paolo. 1983-1985, Tholoi il1 Sardegna: alcul1e realisation 01' the tholos and the external wal1s 01' the considerazioni, in Studi Etruschi (pp. 43-54), tower took place at the same time and on horizontal Cappai-Giuseppe Pulina, Serena Noemi. 1999-2000. Tesi di planes, thus utilizing as a building base those layers Laurea: Torri l1uragiche: caratteristiche tecniche e already constructed. strutturali. 1l caso dei l1uraghi Orolio-Silanus INU) e 6. W. G. Cavanagh and R. R. Laxton «An investigation Ponte- INU). Discussa presso il Dipartimento di into the construction 01' Sardinian Nuraghi», 1987. Costruzioni del1'UniversiÜ¡ degli Studi di Firenze Facolta 7. The building method adopted for 15 nuragic tholoi is di Architettura A. A. Relatori: ProL Luciano Barbi- described as fol1ow in their pubblication: "Our analysis Alberto Bove. is hased on carefÚlly measured sections 01'the domes. A Cavanagh. W. G. and R .R. Laxton. 1987. Nuragic rapid method on surveying lVas devised using lasers. In Sardil1ial1 and the Mycel1aean world, in: Studies in the final sea son this in volved mounting a selllevelling Sardinian Archaeology IlI, Ed. M. Balmuth, BAR rotating laser at the centre 01' the vault, so that a lnternational Series 387 (pp. 39-55). diametric vertical section could be defined. A theodolite Cavanagh, W. G. and R. R. Laxton. 1987. AI1 investigation la Kem DKM2), lVitlz a laser evepiece mounted, lVas set into the costructiol1 ofSardinian Nuraghi, Reprinted from "p as fÚ from the section as space lVould allcllV. Tlze thc papers 01' the Brithish School al Rome, vol. LV (pp. precise location ofthe theodolite in relation /0 the given 2-74). sectiol1 \Vas calcula/ed. The tlVO laser spots lVere tlzen Cavanagh, W. G. and R. R. Laxton. Tlze structural aimed /O concide ot a series o/points rOUl1dthe sections mechal1ics ofthe Mycenaeal1 Tholos Tomh. as defined hy the rotatil1g laser. The positiol1 01' each Di Pasqualc, Salvatore. 1996. L' arte del costruire. Tra poil1t could he calculated from the vertical and cOl1oscenza e sciel1za. Venezia, Ed. Marsi1io. horizontal readings on the theodolite and the known Giarizzo, Francesco. 1923. Sulla tecnica costruttiva degli perpel1dicular distal1ce of the theodollte from the lil1e 01' edifici l1uragici, in: Bullettino di Paletnologia Italiana. the section. This method is sensitive to kl10IVil1g the Giuffré, Anlonino. 1998. Letture sulla meccal1ica delle precise location 01'the theodolite, but our measurement murature storiche, Roma, Ed. Kappa. were jÓwld to he accurated to:t 1%». W. G. Cavanagh Laner. Franco. 1999. Accabadora. Tecnologie delle 544 S. N. Cappai

costruzioni nuragiche, Collana di Architettura, Milano, sopra i nuraghi e loro importanza» di A. M. Centurione, Franco Angeli. , Ed. Solinas. Lilliu, Giovanni. 1962. 1 Nuraghi. Torri preistoriche di Moravetti, Alberto. 1992. 11 cumplessu nuragico di Sardegna, Cagliari, Ed. La Zattera. Palma vera, Sassari, Ed. Carlo Delfino. Lilliu, Giovanni. 1988. La Civilta dei Sardi. Dal Paleolitico Moravetti, Alberto. 1998. Ricerc'he archeologiche nel all'Eta dei nuraghi, Torino, Ed. Nuova Eri. Marghine-Planargia. 11 Marghine-monumenti, Parte 1, Lilliu, Giovanni and Raimondo Zucca. 1988. Su Nuraxi di Sassari, Ed. Carlo Delfino. Barumini, Sassari, Ed. Carlo Delfino. Santillo, Rafaele and Barbro Santillo Frizell. 1987. The Manca, Giacobbe. 1985. Nuraghi: tecniche costruttive, in Nuragic dome. Why false? in: Studies in Sardinian Sardinia Antiga, n° 7 (pp. 18-23), Nuoro. Archaeology IlI, BAR (pp. 57-75). Manca, Giacobbe. 1983. Tipi di nuraghi, tecnica costruttiva Ugas, Giovanni. 1987. Un nuovo contrihuto per lo studio e spunti cronologici, in Sardigna Antiga, n° 2 (pp. della tholos in Sardegna. La fortezza di Su Mulinu- 18-20). , in Studies in Sardinian Archaeology III, Manca, Giacobbe. 1997. Premessa Critica a «Studi recenti BAR.