Xlibris, a German online reference source, has articles on literary periods and authors of German literature. Click on the image and the relevant name or period.
Dictionary of Literary Biography has short biographies of past and present authors, historians, journalists, screenwriters, publishers, and playwrights. Includes bibiographies for primary and secondary literature.
Search Oxford Reference Online for reference articles on literary and historical periods as well as on literary authors. This collection includes hundreds of reference works from Oxford University Press, such as Oxford Companion to German Literature