Google Scholar is a free search engine that indexes scholarly literature from a wide variety of sources, formats, and disciplines. This index includes peer-reviewed academic materials, conference papers and proceedings, dissertations and theses, as well as court opinions and patents.
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Note: Google Scholar will likely produce more cited references than either Web of Science or Scopus, but some of these may be duplicates. Google does not provide a complete list of all the publications it indexes, so it is difficult to know if Google Scholar provides comprehensive citation counts.
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