Proceedings of the international clay conference, 1985 : Denver, Colorado, July 28 to August 2, 1985 / organized by the Clay Minerals Society and the United States Geological Survey under the auspices of Association Internationale pour l¹Etude des Argiles ; - Schultz, Leonard Gene 1926-; Van Olphen, H. 1912-; Mumpton, Frederick Albert 1932- (Clay Minerals Society, 1987)