The Zeitschriftendatenbank (ZDB)  is the world’s largest specialized database for serial titles (journals, annuals, newspapers etc., incl. e-journals). The ZDB actually contains more than 1.7 million bibliographic records of serials from the 16^th century onwards, from all countries, in all languages, held in 4.400 German and Austrian libraries, with 13.6 million holdings information. It does not contain contents, i. e. journal articles.

The Electronic Journals Library is a service to facilitate the use of scholarly journals on the internet. It offers a fast, structured and unified interface to access full-text articles online.
It comprises 83715 titles from all areas of research, 16243 of which are available online only. In addition, 86681 journals, which are provided by aggregators, are listed. The EZB contains 51639 journals which are accessible free of charge to anyone. Furthermore, the participating libraries provide their users access to the journals they subscribe to.

DOAJ is an online directory that indexes and provides access to high quality, open access, peer-reviewed journals.