Zentralblatt MATH (zbMATH) is the world’s most comprehensive and longest-running abstracting and reviewing service in pure and applied mathematics. It is edited by the European Mathematical Society (EMS), the Heidelberg Academy of Sciences and Humanities and FIZ Karlsruhe. The editorial work is done by the Berlin office of FIZ Karlsruhe which, as a member of the Leibniz Association, is a non-profit company and a recognized organisation of public interest. zbMATH is distributed by Springer Nature.

The zbMATH database contains about 4 million bibliographic entries with reviews or abstracts currently drawn from about 3,000 journals and book series, and 180,000 books. The coverage starts in the 18th century and is complete from 1868 to the present by the integration of the "Jahrbuch über die Fortschritte der Mathematik" database.

JournalTOCs is a Current Awareness Service (CAS) where you can discover the newest papers coming directly from the publishers as soon as they have been published online. JournalTOCs is for researchers, librarians, students and anyone who's looking for the latest or most current papers published in the scholarly literature with international coverage. JournalTOCs pulls together a database of Table of Contents (TOCs) from scholarly journals and provides a convenient single "one stop shop" interface to these TOCs.

JournalTOCs is the biggest searchable collection of scholarly journal Tables of Contents (TOCs). It contains articles' metadata of TOCs for over 33,409 journals directly collected from over 3769 publishers. JournalTOCs has taken special care to include all the highest rated journals in their fields, guaranteeing quality results.

Crossref (formerly styled CrossRef) is an official Digital Object Identifier (DOI) Registration Agency of the International DOI Foundation. It is run by the Publishers International Linking Association Inc. (PILA) and was launched in early 2000 as a cooperative effort among publishers to enable persistent cross-publisher citation linking in online academic journals. Crossref is a not-for-profit association of about 2000 voting member publishers who represent 4300 societies and publishers, including both commercial and not-for-profit organizations. Crossref includes publishers with varied business models, including those with both open access and subscription policies.

Crossref interlinks millions of items from a variety of content types, including journals, books, conference proceedings, working papers, technical reports, and data sets. The expense is paid for by Crossref Member publishers. Crossref provides the technical and business infrastructure to provide for this reference linking using Digital Object Identifiers (DOIs). Crossref provides deposit and query service for its DOIs.

ICI World of Journals is a global database dedicated to scientific journals from around the world. The idea of the ICI World of Journals database is to create a possibility for scientific journals from all over the world, of verifying them in terms of using transparent editorial practices.

ICI World of Journals is the third largest international database. In 2014 the number of registered journals amounted to about 22 thousand. Since then, more and more Editorial offices have decided to present their publication achievements to the scientists from all over the world. Currently, there are over 45 thousand journals that are registered in the database and the number of users visiting website exceeds 70 thousand from 150 countries every month.

Google Scholar is a freely accessible web search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines. Google Scholar index includes most peer-reviewed online journals of Europe and America's largest scholarly publishers. This product provides the citation indexing features. While Google does not publish the size of Google Scholar's index, third-party researchers estimated it to contain roughly 160 million documents.

ROAD is the acronym for Directory of Open Access scholarly Resources. This is a free service provided by the ISSN International Centre. ROAD was launched as an independent website in December 2013 by the ISSN International Centre with the support of the Communication and Information Sector of UNESCO. ROAD is now integrated into the ISSN portal and provides a free access to a subset of ISSN bibliographic records. These records describe the scholarly resources in open access that have been identified by the ISSN Network. ROAD is in line with the actions of UNESCO for promoting Open Access to scientific resources. ROAD is complementary to the Global Open Access Portal (GOAP) developed by UNESCO and providing a snapshot of the status of Open Access to scientific information around the world.

WorldCat is the world's largest network of library content and services. WorldCat libraries are dedicated to providing access to their resources on the Web, where most people start their search for information.

Scientific Periodicals of Ukraine (SPU VNLU) — project of Vernadsky National Library of Ukraine (VNLU). Ukrainian scientific periodicals contain articles from international journals in all fields of knowledge and carries out the completion of full-text electronic information resources, electronic counterparts publications or electronic publications provided by the owners. As part of an information resource "Scientific Periodicals of Ukraine" is adjusted full-text search of scientific publications in PDF format. VNLU spent working on the integration of information resource "Scientific Periodicals of Ukraine" to the interface of analytical services, Google Scholar (Google Academy). It contains approximately 2,520 journals; 25,372 — issues; 628,524 — full texts of articles.