@misc{Engel1995, author = {Ulrich Engel}, title = {Ulrich Ammon: Die internationale Stellung der deutschen Sprache, Berlin, New York, de Gruyter, 1991, 633 S.}, editor = {Alois Wierlacher}, volume = {21}, isbn = {3-89129-157-4}, pages = {555 -- 557}, year = {1995} }