por Kidybinski, A [editor] | Dubinsky, J [editor] | International Bureau of Strata Mechanics.
por International Conference Geomechanics 91 (hradec, Ostrava, Checoslovaquia) | Rakowski, Zikmund [editor] | Ceskoslovenska Akademie Ved. Mining Institute | International Bureau of Strata Mechanics | International Society Of Water Jet Technology.