As a Background Source
The purpose of an encyclopedia is to provide basic information about a topic. Within the article, you should encounter important terms, the names of notable people, and background information on the topic. This can help you establish a foundation for your research.
Never Cite a General Encyclopedia Article
This is something that is never done. Never!
Use the Bibliography at the End of an Encyclopedia Article
Sources included are considered classic books and articles on the topic.
Concise Oxford-Duden German Dictionary : German-English, English-German
2nd Floor PF3640 .C69 2005
Deutsches Theater-Lexikon : Biographisches und bibliographisches Handbuch
Encyclopedia of German Literature
2nd Floor PT91 .E53 2000 V.1, V.2
History of German Theater
2nd Floor PN2657 .G73 2006
Modern Germany : an Encyclopedia of History, People, and Culture, 1871-1990 / editors, Dieter K. Buse, Juergen C. Doerr.
2nd Floor DD14 .M64 1998 V.1, V.2