Copernicus Publications has been publishing highly reputable peer-reviewed open access journals since 2001. Through interactive, multi-stage open access publishing, Copernicus aims to bring real transparency into scientific quality assurance. 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 OSF Preprints search combines records from various preprint repositories, including arXiv, bioRxiv, Cogprints, PeerJ, PsyArXiv, RePEc and SocArXiv.

The RISM database references mostly historical music manuscripts, the majority of them originated before 1800. - The original sources are available from the libraries, music archives, and private collections as indicated in the RISM database. These institutions can often be approached for reproductions. - About 700,000 entries (June 2010). -- Die RISM-Datenbank weist hin auf vor allem historische handschriftliche Noten, die Mehrzahl davon entstanden vor 1800. - Die Originale können in den angegebenen Bibliotheken, Musikarchiven oder Privatsammlungen eingesehen werden. Dort können oft auch Reproduktionen herstellen gelassen werden. - Ca. 700.000 Einträge (Juni 2010).

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.