Cogitatio is an academic and community-oriented publisher based in Lisbon, which was founded in 2014 with the aim of promoting the open access dissemination of scientific knowledge. Cogitatio currently publishes 4 peer-reviewed Open Access journals focusing on research in the social sciences and humanities. From January 1, 2023, the Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

Frontiers is a community-oriented open-access academic publisher and research network. It was launched in 2007 by scientists from the Swiss Federal Institute of Technology in Lausanne and aims to provide better tools and services to researchers in the Internet age. Since then, Frontiers has become one of the fastest-growing open-access scholarly publishers: over 400,000 high-quality, peer-reviewed articles have been published in about 200 community-driven journals across more than 300 specialty niches in science, medicine and technology. The Max Planck Society covers article-processing charges for Max Planck authors centrally. Further details are available on the MPDL website.

The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers in astronomy and physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 13 million records covering publications in Astronomy and Astrophysics, Physics, and the arXiv e-prints. Abstracts and full-text of major astronomy and physics publications are indexed and searchable through the new ADS modern search form as well as a classic search form.

SSOAR collects electronic full texts from the domain of the Social Sciences and makes these texts available according to the Berlin Declaration on Open Access to Scientific Knowledge.