Walter De Gruyter publishes a wide variety of content covering humanities, medicine, the sciences and law. The "De Gruyter Online" platform provides access to title information and the electronic content for De Gruyter journals and books under one roof. Users from the MPG have access to following products: * De Gruyter Journals and Yearbooks - current content of selected serial titles available on the platform (last 13 volumes) * De Gruyter Journal Archive - backfile content of 150 titles * De Gruyter Online / Research Now E-Journal Archive - about 50 journals focusing on research in economics, formerly published by Berkeley Electronic Press until 2022 * De Gruyter eBooks - a collection of purchased e-books which is continuously extended by single e-book acquisitions by MPG libraries

Karger is a scientific publisher of journals and books in all medical areas, including immunology, genetics, oncology, nephrology, neurology, cellular and molecular biology. MPG staff has full text access to the current content of the entire Karger journal collection and selected eBooks. In addition, the agreement covers arising article-processing charges for Max Planck authors in Karger hybrid and Gold Open Access journals. Further details are available on the MPDL website.

"Psyndex - Tests" contains records on psychology from researchers in Germany, Austria, and Switzerland. Compiled by the Leibniz Institute for Psychology Information (ZPID), this database covers about 5,000 extensive descriptions of psychological and educational tests used in the German-speaking countries. "Psyndex - Tests" is bilingual: titles and descriptors are in German and English. German publications are abstracted in German; English publications in English. The database also include theoretical background, testing procedures, test construction, reliability, validity, fields of application, research and other selected literature, a comprehensive discussion, and test reviews. "Psyndex - Tests" is indexed with the Thesaurus of Psychological Index Terms by permission of the American Psychological Association (APA). A bilingual thesaurus is included with the database.