@incollection{HeidenG{\"o}bel2000, author = {Heiden, W. and G{\"o}bel, M.}, title = {Virtuelle Umgebungen}, booktitle = {Szczerbicka, Uthmann (Eds.): Modellierung, Simulation und K{\"u}nstliche Intelligenz. Statusband}, isbn = {1-56555-128-1}, institution = {Fachbereich Informatik}, pages = {139 -- 173}, year = {2000}, language = {en} }