[1] Merck and Co. Inc., “The Merck Index,” 9th Edition, Whitehouse Station, 1976, p. 4096.
[2] H. Rosch and J. Schwarz, “Damaged to Frescoes Caused by Sulphate-Bearing Salts: Where Does the Sulphur Come from?” Studies in Conservation, Vol. 38, No. 4, 1993, pp. 224-230. doi:10.2307/1506367
[3] G. L. Martinez and J. M. Navarrete, “Use of a Radiotracer to Test and Reduce the Porosity and Humidity Absorption from the Soil in Pre-Hispanic Raw Materials,” Journal of Radioanalytical and Nuclear Chemistry, Vol. 263, No. 1, 2005, pp. 35-38. doi:10.1007/s10967-005-0008-2
[4] G. L. Martinez and J. M. Navarrete, “A New Technique to Preserve Raw Materials of Ancient Monuments against the Humidity and Its Test Using 22Na Labelled Solutions,” Journal of Radioanalytical and Nuclear Chemistry, Vol. 274, No. 3, 2007, pp. 651-655. doi:10.1007/s10967-007-7097-z