Google Scholar is a freely accessible web search engine that indexes the full text of scholarly literature across an array of publishing formats and disciplines.

ProQuest's CSA Illumina database pertains to research and application in the field of computer science, which is updated on a monthly basis.

EBSCO Publishing, headquartered in Ipswich, Massachusetts, is an aggregator of full-text content. EBSCO Publishing's core business is providing online databases via EBSCOhost to libraries.

CiteSeerX is a public academic database, digital library and repository for scientific and academic papers with a focus on computer and information science at the College of Information Sciences and Technology, Pennsylvania State University.

WorldCat is a union catalog which itemizes the collections of 71,000 libraries in 112 countries which participate in the Online Computer Library Center (OCLC) global cooperative. It is built and maintained collectively by the participating libraries. It is forty years old today.