DigiZeitschriften is a digital library containing digitized back issues of core German research journals. At the moment the platform provides full-text access to more than 600 journals dating back to 1850. The archive content is edited on an ongoing basis. Any existing gaps will be filled and missing data steadily added. Users from the MPG have access to the complete journal collection, older public domain content is available free of charge to anyone.

ProQuest Dissertations and Theses Global is the world's most comprehensive collection of dissertations and theses, covering materials back to the first U.S. dissertation, accepted in 1861, as well as to European dissertations from the 17th century. The database is the official dissertations repository for the Library of Congress, with 5.5 million bibliographic citations, 3 million full texts, 4,100 contributing institutions worldwide and 250,000 works added annually. Full-text coverage spans from 1743 to the present, with citation coverage dating back to 1637.

Olms Online is an e-book portal providing access to following collections: * Reprints: About 400 volumes with a focus on German language and literature and on philosophy. Olms Online presents titles with additional information. These are reprints with new introductions, afterwords, notes or indexes added by the editors. * Frankfurt and Leipzig Book Fair Catalogues: Book-trade catalogues, generally referred to as book fair catalogues, offer a unique overview of German and European book production over a period of nearly 300 years (1594-1860).

Since the publication of its first installment in 1976 the Theologische Realenzyklopädie has provided a comprehensive account of the state of theological research. Some 2000 articles present a multitude of historical and theological data in their context of faith and thought, theology and religion. A multidisciplinary approach integrates into the theological account not only the disciplines of Old Testament and New Testament Studies, Church History, and Systematic and Practical Theology but also Judaic Studies, Religious Studies and Philosophy.