@techreport{ErdmannHoppeKornhuber1993, author = {Bodo Erdmann and Ronald H. W. Hoppe and Ralf Kornhuber}, title = {Adaptive Multilevel-Methods for Obstacle Problems in Three Space Dimensions.}, institution = {ZIB}, address = {Takustr. 7, 14195 Berlin}, number = {SC-93-08}, language = {eng}, year = {1993} }