OLC Economic Sciences is a subject oriented selection of bibliographic data from the Online Contents database that is regularly enhanced by table of contents data from 3,150 additional periodicals with more than 4,500,000 records of articles out of the special collections of the ZBW – Leibniz-Informationszentrum Wirtschaft and the university library of the Helmut Schmidt university, Federal Armed Forces, Hamburg.

The database OLC Ibero-America, Spain and Portugal is a regional related section from the Online Contents database that is constantly being completed with the addition of selected journals from the competent Libraries, the Library of the Ibero-American Institute Prussian Cultural Heritage (Ibero-America and the Caribbean) and the state and university library SUB Hamburg (Spain and Portugal). Currently more than 1.400 journals are being indexed. Gradually earlier editions of these journals will also be made accessible.

The multidisciplinary database OLC International Relations and Area Studies contains table of contents of journals from several special subject collections, including political science, economics, the Middle East and other regional special subject collections. It offers a multidisciplinary selection from the Online Contents database, with additional input from other special subject collections. The International Relations and Area Studies section currently covers approximately 797 journals.

The database OLC Mathematics and Informatics is a subject oriented selection of bibliographic data from the Online Contents database that is regularly enhanced by table of contents data from additional periodicals out of the special collections of the TIB Hannover. Currently 1,357 journals are being indexed back to the year of publication in 1993.

The OSF Preprints search combines records from various preprint repositories, including arXiv, bioRxiv, Cogprints, PeerJ, PsyArXiv, RePEc and SocArXiv.

ScienceOpen is a networking platform for scholars to enhance their research in the open, make an impact, and receive credit for it. The site provides advanced search and discovery functions, combined with post-publication peer review, recommendation, social sharing, and collection-building features. The Max Planck Society covers article-processing charges for ScienceOpen Research and ScienceOpen Poster centrally. Further details are available on the MPDL website.

References within the fields of business, economics, credit management and ergonomics are searchable via a single interface. An overview of included resources is available via https://www.wiso-net.de/sourceInformation/categoryNavigation?searchId=%3A3%3AWIR....

zbMATH Open (formerly known as Zentralblatt MATH) is the world's most complete and longest running abstracting and reviewing service in pure and applied mathematics. The MATH Database contains several million entries drawn from more than 3,500 serials and journals, and more than 1,100 book series and monographs. The entries are classified according to the Mathematics Subject Classification Scheme (MSC 2000).