International Clay Conference Bologna and Pavia, Italy, Association internationale pour l'étude des argiles. Gruppo italiano, Van Olphen, H., & Veniale, F. (1982). International Clay Conference, 1981: Proceedings of the VII International Clay Conference, 1981, held in Bologna and Pavia, Italy, September 6-12, 1981, organized by the Italian Group of AIPEA, under the auspices of Association internationale pour l'étude des argiles. Elsevier Scientific Pub. Co..

International Clay Conference Bologna and Pavia, Italy, Association internationale pour l'étude des argiles. Gruppo italiano, H. Van Olphen, e F. Veniale. International Clay Conference, 1981: Proceedings of the VII International Clay Conference, 1981, Held in Bologna and Pavia, Italy, September 6-12, 1981, Organized by the Italian Group of AIPEA, Under the Auspices of Association Internationale Pour L'étude Des Argiles. Amsterdam ; New York: Elsevier Scientific Pub. Co., 1982.

International Clay Conference Bologna and Pavia, Italy, et al. International Clay Conference, 1981: Proceedings of the VII International Clay Conference, 1981, Held in Bologna and Pavia, Italy, September 6-12, 1981, Organized by the Italian Group of AIPEA, Under the Auspices of Association Internationale Pour L'étude Des Argiles. Elsevier Scientific Pub. Co., 1982.