Geological Sciences Inst.
Mary A. Vance
Sofiane Amziane
Richard D. Barksdale
Valentin V. Tepordei
Jianzhuang Xiao
Victor Saouma
Department of the Environment Staff Great Britain
Mark G. Alexander
Unknown Author
P. M. Harris
David A. Lindsey
Underwood, McLellan & Associates.
North Wales Working Party on Aggregates.
Leonid Dvorkin