ProQuest Dissertations and Theses Global is the world's most comprehensive collection of dissertations and theses, covering materials back to the first U.S. dissertation, accepted in 1861, as well as to European dissertations from the 17th century. The database is the official dissertations repository for the Library of Congress, with 5.5 million bibliographic citations, 3 million full texts, 4,100 contributing institutions worldwide and 250,000 works added annually. Full-text coverage spans from 1743 to the present, with citation coverage dating back to 1637.

The goal of OAIster is to create a collection of previously difficult-to-access, academically-oriented digital resources that is easily searchable by anyone.

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).