1. Abstract & Introduction Results and Discussions
References
Conclusion
Methodology
Abstract: This research is a chemical analytical approach to the
characterization of 37 ancient pottery sherds from an archaeological site of
Dedan (Saudi Arabia). Inductively coupled plasma–mass spectrometry and
multivariate statistical analysis (SAS & SPSS) were used to determine 29
elemental properties of the pottery fragments and to identify individual
groups among the samples studied. The study findings indicated that the
existence of four major groups of the pottery fragments: Abbasid , Nabataean,
Tyama and Dedan pottery. The principal component analysis and cluster
analysis validated the existing these groups .
Introduction: The geographical position of the Arabian Peninsula, situated
between the ancient civilizations of India, Persia, the states of the eastern
Mediterranean and Egypt, contributed to the Peninsula becoming an important
center of trade and commerce, and to the emergence of several Arab states
along the trading routes of the Peninsula. Dedan ( al-Khuraybah) is one of the
famous archeological site in Al-Ula, North-west of Saudi Arabia. The town
was one of the main settlements of North-west Arabian peninsula during the
1st millennium B.C. the ancient town was located on the ancient spice road
connecting Arabia with Egypt, Syria and Mesopotamia (map.1&photo.1).
The objective: A major objective of research efforts is to determine the
elemental composition of the pottery fragments from the Dedan site, using the
multivariate methods, CA and PCA, and potentially to distinguish individual
groups of samples and to verify if the chemical differences reflect the
archaeologists’ classification of the archeological objects .
Sample digestion for ICP-MS analysis
Samples were digested with concentrated high-purity acids as follows.
Approximately, (0.1-0.15g) samples were digested in HNO3 (69%), HCL (34%)
and HF (43%) in microwave digestion system a 12-vessel (fluoropolymer)
multi-prep router.
For our experiments, ten of the vessels were used to digest archaeological
samples, one vessel was reserved for a blank sample, and the remaining vessel
was set aside for the quality control sample (BHOV-2). The samples were cold-
digested for 20 min prior to microwave digestion. The heating programme
consisted of a 50 min ramp to 200°C where the temperature was held for 30
min at 50 bar, The cooled digests were diluted, Followed by a second, 10-fold
dilution, A diluent containing Rh as the internal standard was used to make the
second dilution.
Sample Selection
37 ancient pottery shards were obtained from archeology college, King Saud
University. These objects are approximately dated from half first millennium
B.C to 9th century A.D. according to archeological records , 15 pottery
fragments are belong to Dedan period (D1toD15), 10 belong to Nabatean
period 1st century A.D (N-1 to N-10) , 7 belong to Abbasid Caliphate period
(around 9th century A.D), (Ab-1 to Ab-8) and 3 are classified as Tayma
pottery (M1 to M3). All these pottery shards were excavated from Dedan (al-
Khuraybah) heritage site (26°39'18.3"N ,37°54'49.2"E),in 2008 and 2010 ,(
5th
&7th) excavation seasons in al-Ula , North west Saudi Arabia
Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
The analytical methods used in this study are inductively-coupled plasma
spectrometry (ICP-MS). ICP-MS was used to determine the chemical
composition of targeted areas of the paste (Fig.1.
Map.1Location map of (Dedan)
&photo.1 part of ancient town of
Dedan (2015)
Samples of pottery shards
29 elemental concentrations of 37 pottery samples are presented in ug/g in Table
1. reference material (USGS ,Basalt, Hawaiian Volcanic Observatory, BHVO-2)
was used to gauge the accuracy of elemental concentration data (Tabl.1).
Fig 4. 3D Bivariate plots corresponding to
the of some elements in pottery shards
Fig.2. Dendrogram using words methods of 37 pottery samples.
Table 1. Chemical results of the Dedan execration site of the pottery
shards (in ug/g).
Fig1. Steps in the chemical analysis of ancient pottery.
Fig. 3. – Multivariate analysis PCA
This study demonstrates that high-precision ICP-MS element analysis is very
powerful for characterization of archaeological pottery shards .
The analysis of 37 fragments of ancient pottery from Dedan heritage site
indicated the existence of four different types of potteries. Multivariate
analysis using principle component and clustering confirmed these pottery
groups and interpreted them in plots and dendrogram.
Cluster Analysis CA
The cluster analysis employed the words method using 29 variables
(Li,Be,Sc,Ti,V,Cr,Mn,Co,Ni,Zn,Ga,Rb,Sr,Y,Zr,Cs,Ba,La,Ce,Sm,Tb,Dy,Yb,Lu,Hf
,Tl,Pb,Th&U) (Fig.2). The resulting dendrogram illustrated that the data set of
37 fragments had two main parts, one of them made up of two groups ( Abbased
& Nabataean), and the other part made up as well of two groups ( Dedan and
Tayma).
Principle components analysis
The chemical data were statistically analyzed using the PCA (principle
components analysis) method processed on the 8th version of the SAS software.
The first principal component explains 37.93% of the total sample variance.
The first two principal components, collectively, explain 57.99% of the total
sample variance . Consequently, sample variation is summarized very well by
two principal components and a reduction in the data from 37 observations on
29 variables to 37 observations on 2 principal components is reasonable .
Fig.3&4. shows the scatter plot of the four groups of pottery shards ( 1-
Abbasid , 2- Nabateaean, 3- Madian (Tayma) and 4- Dedan )
Id BHVO-2 BHVO-2 D-1 D-2 D-3 D-4 D-5 D-6 D-7 D-8 D-9 D-10 D-11 D-12 D-13 D-14 D-15
Li 5 3.80±0.77 14.91 14.63 25.03 10.24 13.36 12.28 12.71 11.92 14.73 18.32 10.61 14.17 20.84 11.98 12.61
Be - 1.3 1.84 2.82 1.98 1.4 1.4 1.6 1.87 1.75 1.92 2.02 2.3 2.38 1.34 1.55
Sc 32±1 -8.53 -21.73 6.17 32.12 50.59 44.4 67.09 57.16 56.17 79.77 80.88 85.23 109.08 76.79 61.32
Ti 16300±200 15600±600 6090.91 5282.83 4934.29 6097.24 5523.25 5106.67 6243.13 5423.57 4627.38 7089.55 6122.69 5094.63 7800.99 6122.19 5143.82
V 317±11 317±16 154.2 107.88 146.53 140.06 172.69 113.03 176.64 127.45 100.61 147.03 186.25 146.25 217.86 208.21 116.38
Cr 280±19 283±17 194.61 106.93 117.39 156.87 172.45 81.53 196.02 105.6 85.04 134.89 211.42 92.2 165.48 194.11 81.76
Mn 1290±40 1305±26 316.48 491.16 1096.76 626.81 362.43 283.27 383.13 858.71 881.84 2182.91 439.13 534.27 1360.82 296.77 679.4
Co 45±3 47.30±2.01 30.8 19.54 28.22 87.85 22.36 18.02 40.37 42.22 19.51 44.95 50.98 111.51 83.6 53.64 14.2
Ni 119 ±7 122±5.76 79.87 67.1 76.72 90.82 58.79 47.86 83.3 74.38 55.58 65.45 83.22 49.04 64.23 77.82 51.19
Zn 103±6 97.96±6 44.86 48.87 84.84 61.62 45.6 54.09 56.68 85.61 52.93 129.3 46.16 76.52 141.47 49.17 68.98
Ga 21.7±0.9 22.50±1.27 24.14 26.16 31.92 28.96 25.12 34.24 27.42 33.71 28.73 46.3 26.31 39.19 44.03 26.35 34.43
Rb 9.8±1 9.47±0.58 34.7 34.47 33.76 17.07 21.76 23.14 23.34 26.13 23.63 14.17 7 59.39 41.38 6 9.78
Sr 389±23 391±30 446.94 964.38 308.76 580.31 650.49 923.63 639.62 763.7 923.53 287.33 680.14 938.8 646 444.26 829.74
Y 26±2 22±3.46 13.28 24.8 20.95 15.13 12.92 29.31 19.12 25.09 27.22 9.69 9.15 36.08 24.51 7.89 20.18
Zr 172±11 178±10 124.68 120.05 105.57 132.36 126.33 85.28 126.74 128.43 97.85 89.39 127.01 121.79 86.82 126.03 86.98
Pd - - 10.12 4.57 3.09 3.02 2.48 1.88 2.18 2.09 1.65 1.52 1.95 1.93 1.34 1.78 1.18
Cs - 2.52 1.59 2.62 1.1 1.11 1.4 1.26 1.14 1.15 3.11 0.6 2.94 4.36 0.55 0.69
Ba 130±13 125±12 197.29 275.55 465.09 321.55 270.15 311.63 253.59 379.72 323.18 958.44 227.83 455.41 583.48 208.01 319.84
La 15±1 15.74±1.77 22.73 49.63 26.88 24.88 27.45 55.17 34.48 45.68 48.26 7.3 13.17 63.53 27.5 10.92 34.73
Ce 38±2 37.48±3.80 57.46 116.99 74.24 77.24 72.11 138.33 93.16 115.32 115.03 19.8 34.41 133.41 69.88 30.48 89.92
Sm 6.2±0.4 6.06±0.69 5.39 8.47 6.1 5.82 5.09 10.89 7.24 8.71 8.78 3.05 3.61 11.5 7.78 3.15 8.2
Tb 0.9 0.88±0.1 1.49 1.4 0.95 0.97 0.83 1.54 1.12 1.27 1.22 0.41 0.57 1.61 1.19 0.49 1.18
Dy - 3.75+.30 4.54 6.62 5.04 4.82 4.12 7.44 5.94 6.54 6.62 2.4 3.31 8.54 6.3 2.86 5.98
Yb 2±0.2 1.7±.03 1.75 1.97 2.24 1.47 1.58 2.41 1.57 2.13 2.13 1.1 1.08 2.88 2.08 1.09 1.76
Lu 0.28±0.01 0.26±.03 0.65 0.36 0.36 0.22 0.19 0.32 0.25 0.31 0.31 0.15 0.15 0.42 0.3 0.15 0.24
Hf 4.1±0.3 3.93±0.3 5.31 3.06 2.87 2.96 2.91 2.42 2.81 3.14 2.43 2.23 2.98 3.1 2.24 2.97 2.26
Ta 1.4 1.48±.1 118.57 22.05 11.05 8.54 6.6 4.61 3.84 3.86 2.81 2.15 2.92 2.67 8.84 2.56 2.18
Tl - 0.057±0.01 0.94 0.41 0.37 0.18 0.28 0.22 0.2 0.14 0.12 0.6 0.18 0.29 0.37 0.17 0.15
Pb - - 33.06 27.76 29.74 21.33 31.77 61.93 37.26 44.68 37.27 43.46 34.33 51.4 58.56 34.84 56.29
Th 1.2±0.3 1.06±0.19 10.25 12.63 8.42 8.48 8.83 17.48 10.4 12.82 13 3.46 6.6 18.62 8.97 6.94 12.11
U - 0.46±0.06 4.28 3.91 3.37 3.47 3.75 3.8 3.6 3.85 4.16 3.03 3.08 5.52 3.55 4.23 3.81
Statistical analysis of data
Two main types of multivariate statistical treatments were applied to the
elemental data: classification Technique, (PCA and CA) aiming to partition the
ancient pottery shards into groups of similar composition, and factorial
technique , of which only principle component analysis (PCA) has been used
mainly as data reduction & interpretative tool. This statistical method is
powerful to validate and clarifying archaeological hypothesis, offering an
additional tool in respect of simple visual examination and stylistic
classification.
AL-Balawi A,N , Alghamdi , A. H. , Al-Dayel,O.A , Alghamdi, S.A & Al Nachawati,H
Elemental study of pottery sherds from an archaeological site Of Dedan (North-
west Arabian peninsula) , using ICP-MS and multivariate statistical analysis)
D8D1 D2 D3 D6D4 D5 D7 D9 D12D11D10 D13
D14 D15 N-1 N-3 N-6N-4
N-2 N-8N-7 N-10 Ab-2Ab-1 Ab-4
Ab-7Ab-6Ab-5 Ab-13Ab-12Ab-11Ab-8 M-1 M-3
Photo. ncient Jar , shards & sample powder
[1] Bower, N. W., and Snow , D. H, New Mexico Geological Society, Albuquerque. . 1984,, 291–295.
[2] Klein, M., Jesse, F., Kasper, H.U. & Gölden, A, Archaeometry, 46, 2004. 339-356.
[3] Barone, G., Ioppolo, S., Majolino, D., Migliardo, P. & Tigano, G. Journal of Cultural Heritage, 2002, 145-153.
![Abstract & Introduction Results and Discussions
References
Conclusion
Methodology
Abstract: This research is a chemical analytical approach to the
characterization of 37 ancient pottery sherds from an archaeological site of
Dedan (Saudi Arabia). Inductively coupled plasma–mass spectrometry and
multivariate statistical analysis (SAS & SPSS) were used to determine 29
elemental properties of the pottery fragments and to identify individual
groups among the samples studied. The study findings indicated that the
existence of four major groups of the pottery fragments: Abbasid , Nabataean,
Tyama and Dedan pottery. The principal component analysis and cluster
analysis validated the existing these groups .
Introduction: The geographical position of the Arabian Peninsula, situated
between the ancient civilizations of India, Persia, the states of the eastern
Mediterranean and Egypt, contributed to the Peninsula becoming an important
center of trade and commerce, and to the emergence of several Arab states
along the trading routes of the Peninsula. Dedan ( al-Khuraybah) is one of the
famous archeological site in Al-Ula, North-west of Saudi Arabia. The town
was one of the main settlements of North-west Arabian peninsula during the
1st millennium B.C. the ancient town was located on the ancient spice road
connecting Arabia with Egypt, Syria and Mesopotamia (map.1&photo.1).
The objective: A major objective of research efforts is to determine the
elemental composition of the pottery fragments from the Dedan site, using the
multivariate methods, CA and PCA, and potentially to distinguish individual
groups of samples and to verify if the chemical differences reflect the
archaeologists’ classification of the archeological objects .
Sample digestion for ICP-MS analysis
Samples were digested with concentrated high-purity acids as follows.
Approximately, (0.1-0.15g) samples were digested in HNO3 (69%), HCL (34%)
and HF (43%) in microwave digestion system a 12-vessel (fluoropolymer)
multi-prep router.
For our experiments, ten of the vessels were used to digest archaeological
samples, one vessel was reserved for a blank sample, and the remaining vessel
was set aside for the quality control sample (BHOV-2). The samples were cold-
digested for 20 min prior to microwave digestion. The heating programme
consisted of a 50 min ramp to 200°C where the temperature was held for 30
min at 50 bar, The cooled digests were diluted, Followed by a second, 10-fold
dilution, A diluent containing Rh as the internal standard was used to make the
second dilution.
Sample Selection
37 ancient pottery shards were obtained from archeology college, King Saud
University. These objects are approximately dated from half first millennium
B.C to 9th century A.D. according to archeological records , 15 pottery
fragments are belong to Dedan period (D1toD15), 10 belong to Nabatean
period 1st century A.D (N-1 to N-10) , 7 belong to Abbasid Caliphate period
(around 9th century A.D), (Ab-1 to Ab-8) and 3 are classified as Tayma
pottery (M1 to M3). All these pottery shards were excavated from Dedan (al-
Khuraybah) heritage site (26°39'18.3"N ,37°54'49.2"E),in 2008 and 2010 ,(
5th
&7th) excavation seasons in al-Ula , North west Saudi Arabia
Department of Chemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
The analytical methods used in this study are inductively-coupled plasma
spectrometry (ICP-MS). ICP-MS was used to determine the chemical
composition of targeted areas of the paste (Fig.1.
Map.1Location map of (Dedan)
&photo.1 part of ancient town of
Dedan (2015)
Samples of pottery shards
29 elemental concentrations of 37 pottery samples are presented in ug/g in Table
1. reference material (USGS ,Basalt, Hawaiian Volcanic Observatory, BHVO-2)
was used to gauge the accuracy of elemental concentration data (Tabl.1).
Fig 4. 3D Bivariate plots corresponding to
the of some elements in pottery shards
Fig.2. Dendrogram using words methods of 37 pottery samples.
Table 1. Chemical results of the Dedan execration site of the pottery
shards (in ug/g).
Fig1. Steps in the chemical analysis of ancient pottery.
Fig. 3. – Multivariate analysis PCA
This study demonstrates that high-precision ICP-MS element analysis is very
powerful for characterization of archaeological pottery shards .
The analysis of 37 fragments of ancient pottery from Dedan heritage site
indicated the existence of four different types of potteries. Multivariate
analysis using principle component and clustering confirmed these pottery
groups and interpreted them in plots and dendrogram.
Cluster Analysis CA
The cluster analysis employed the words method using 29 variables
(Li,Be,Sc,Ti,V,Cr,Mn,Co,Ni,Zn,Ga,Rb,Sr,Y,Zr,Cs,Ba,La,Ce,Sm,Tb,Dy,Yb,Lu,Hf
,Tl,Pb,Th&U) (Fig.2). The resulting dendrogram illustrated that the data set of
37 fragments had two main parts, one of them made up of two groups ( Abbased
& Nabataean), and the other part made up as well of two groups ( Dedan and
Tayma).
Principle components analysis
The chemical data were statistically analyzed using the PCA (principle
components analysis) method processed on the 8th version of the SAS software.
The first principal component explains 37.93% of the total sample variance.
The first two principal components, collectively, explain 57.99% of the total
sample variance . Consequently, sample variation is summarized very well by
two principal components and a reduction in the data from 37 observations on
29 variables to 37 observations on 2 principal components is reasonable .
Fig.3&4. shows the scatter plot of the four groups of pottery shards ( 1-
Abbasid , 2- Nabateaean, 3- Madian (Tayma) and 4- Dedan )
Id BHVO-2 BHVO-2 D-1 D-2 D-3 D-4 D-5 D-6 D-7 D-8 D-9 D-10 D-11 D-12 D-13 D-14 D-15
Li 5 3.80±0.77 14.91 14.63 25.03 10.24 13.36 12.28 12.71 11.92 14.73 18.32 10.61 14.17 20.84 11.98 12.61
Be - 1.3 1.84 2.82 1.98 1.4 1.4 1.6 1.87 1.75 1.92 2.02 2.3 2.38 1.34 1.55
Sc 32±1 -8.53 -21.73 6.17 32.12 50.59 44.4 67.09 57.16 56.17 79.77 80.88 85.23 109.08 76.79 61.32
Ti 16300±200 15600±600 6090.91 5282.83 4934.29 6097.24 5523.25 5106.67 6243.13 5423.57 4627.38 7089.55 6122.69 5094.63 7800.99 6122.19 5143.82
V 317±11 317±16 154.2 107.88 146.53 140.06 172.69 113.03 176.64 127.45 100.61 147.03 186.25 146.25 217.86 208.21 116.38
Cr 280±19 283±17 194.61 106.93 117.39 156.87 172.45 81.53 196.02 105.6 85.04 134.89 211.42 92.2 165.48 194.11 81.76
Mn 1290±40 1305±26 316.48 491.16 1096.76 626.81 362.43 283.27 383.13 858.71 881.84 2182.91 439.13 534.27 1360.82 296.77 679.4
Co 45±3 47.30±2.01 30.8 19.54 28.22 87.85 22.36 18.02 40.37 42.22 19.51 44.95 50.98 111.51 83.6 53.64 14.2
Ni 119 ±7 122±5.76 79.87 67.1 76.72 90.82 58.79 47.86 83.3 74.38 55.58 65.45 83.22 49.04 64.23 77.82 51.19
Zn 103±6 97.96±6 44.86 48.87 84.84 61.62 45.6 54.09 56.68 85.61 52.93 129.3 46.16 76.52 141.47 49.17 68.98
Ga 21.7±0.9 22.50±1.27 24.14 26.16 31.92 28.96 25.12 34.24 27.42 33.71 28.73 46.3 26.31 39.19 44.03 26.35 34.43
Rb 9.8±1 9.47±0.58 34.7 34.47 33.76 17.07 21.76 23.14 23.34 26.13 23.63 14.17 7 59.39 41.38 6 9.78
Sr 389±23 391±30 446.94 964.38 308.76 580.31 650.49 923.63 639.62 763.7 923.53 287.33 680.14 938.8 646 444.26 829.74
Y 26±2 22±3.46 13.28 24.8 20.95 15.13 12.92 29.31 19.12 25.09 27.22 9.69 9.15 36.08 24.51 7.89 20.18
Zr 172±11 178±10 124.68 120.05 105.57 132.36 126.33 85.28 126.74 128.43 97.85 89.39 127.01 121.79 86.82 126.03 86.98
Pd - - 10.12 4.57 3.09 3.02 2.48 1.88 2.18 2.09 1.65 1.52 1.95 1.93 1.34 1.78 1.18
Cs - 2.52 1.59 2.62 1.1 1.11 1.4 1.26 1.14 1.15 3.11 0.6 2.94 4.36 0.55 0.69
Ba 130±13 125±12 197.29 275.55 465.09 321.55 270.15 311.63 253.59 379.72 323.18 958.44 227.83 455.41 583.48 208.01 319.84
La 15±1 15.74±1.77 22.73 49.63 26.88 24.88 27.45 55.17 34.48 45.68 48.26 7.3 13.17 63.53 27.5 10.92 34.73
Ce 38±2 37.48±3.80 57.46 116.99 74.24 77.24 72.11 138.33 93.16 115.32 115.03 19.8 34.41 133.41 69.88 30.48 89.92
Sm 6.2±0.4 6.06±0.69 5.39 8.47 6.1 5.82 5.09 10.89 7.24 8.71 8.78 3.05 3.61 11.5 7.78 3.15 8.2
Tb 0.9 0.88±0.1 1.49 1.4 0.95 0.97 0.83 1.54 1.12 1.27 1.22 0.41 0.57 1.61 1.19 0.49 1.18
Dy - 3.75+.30 4.54 6.62 5.04 4.82 4.12 7.44 5.94 6.54 6.62 2.4 3.31 8.54 6.3 2.86 5.98
Yb 2±0.2 1.7±.03 1.75 1.97 2.24 1.47 1.58 2.41 1.57 2.13 2.13 1.1 1.08 2.88 2.08 1.09 1.76
Lu 0.28±0.01 0.26±.03 0.65 0.36 0.36 0.22 0.19 0.32 0.25 0.31 0.31 0.15 0.15 0.42 0.3 0.15 0.24
Hf 4.1±0.3 3.93±0.3 5.31 3.06 2.87 2.96 2.91 2.42 2.81 3.14 2.43 2.23 2.98 3.1 2.24 2.97 2.26
Ta 1.4 1.48±.1 118.57 22.05 11.05 8.54 6.6 4.61 3.84 3.86 2.81 2.15 2.92 2.67 8.84 2.56 2.18
Tl - 0.057±0.01 0.94 0.41 0.37 0.18 0.28 0.22 0.2 0.14 0.12 0.6 0.18 0.29 0.37 0.17 0.15
Pb - - 33.06 27.76 29.74 21.33 31.77 61.93 37.26 44.68 37.27 43.46 34.33 51.4 58.56 34.84 56.29
Th 1.2±0.3 1.06±0.19 10.25 12.63 8.42 8.48 8.83 17.48 10.4 12.82 13 3.46 6.6 18.62 8.97 6.94 12.11
U - 0.46±0.06 4.28 3.91 3.37 3.47 3.75 3.8 3.6 3.85 4.16 3.03 3.08 5.52 3.55 4.23 3.81
Statistical analysis of data
Two main types of multivariate statistical treatments were applied to the
elemental data: classification Technique, (PCA and CA) aiming to partition the
ancient pottery shards into groups of similar composition, and factorial
technique , of which only principle component analysis (PCA) has been used
mainly as data reduction & interpretative tool. This statistical method is
powerful to validate and clarifying archaeological hypothesis, offering an
additional tool in respect of simple visual examination and stylistic
classification.
AL-Balawi A,N , Alghamdi , A. H. , Al-Dayel,O.A , Alghamdi, S.A & Al Nachawati,H
Elemental study of pottery sherds from an archaeological site Of Dedan (North-
west Arabian peninsula) , using ICP-MS and multivariate statistical analysis)
D8D1 D2 D3 D6D4 D5 D7 D9 D12D11D10 D13
D14 D15 N-1 N-3 N-6N-4
N-2 N-8N-7 N-10 Ab-2Ab-1 Ab-4
Ab-7Ab-6Ab-5 Ab-13Ab-12Ab-11Ab-8 M-1 M-3
Photo. ncient Jar , shards & sample powder
[1] Bower, N. W., and Snow , D. H, New Mexico Geological Society, Albuquerque. . 1984,, 291–295.
[2] Klein, M., Jesse, F., Kasper, H.U. & Gölden, A, Archaeometry, 46, 2004. 339-356.
[3] Barone, G., Ioppolo, S., Majolino, D., Migliardo, P. & Tigano, G. Journal of Cultural Heritage, 2002, 145-153.](https://image.slidesharecdn.com/posterconference66-11-2016-190920130146/85/Poster-template-1-320.jpg)
