Created by the Association of College and Research Libraries, this is a very comprehensive research guide on research strategies for German studies, including extensive listings of national libraries and archives of German-speaking countries. An excellent resource for more advanced research in German.
Articles and Databases for Scholarship and News in German
Modern literature, language, linguistics, and folklore journal articles and books, including scholarship on German literature. Includes a language limiter in the search interface to find scholarship written in German, as well.
Topical bibliographies in the humanities and social sciences. Oxford Bibliography
Oxford Bibliographies offers peer-reviewed annotated bibliographies on specific topics in a growing range of subject areas. There are at least 50 specific topical bibliographies in each subject area. Each of these features an introduction to the topic. Bibliographies are browsable by subject area and are keyword searchable.
This is a sample search of "German Literature" in Oxford Bibliographies. There are a number of annotated bibliographies that mention German literature, it might be helpful to browse around these and find more information. Many of these bibliographies include scholarship in both English and German.