PsycINFO®, from the American Psychological Association (APA), contains more than 2.4 million citations and summaries of scholarly journal articles, book chapters, books, and dissertations, all in psychology and related disciplines, dating as far back as the early 1800s. 98 percent of the covered material is peer-reviewed. The database also includes information about the psychological aspects of related fields such as medicine, psychiatry, nursing, sociology, education, pharmacology, physiology, linguistics, anthropology, business, law and others. Journal coverage, which spans 1887 to present, includes international material selected from more than 2,200 periodicals in more than 27 languages. PsycINFO is indexed with controlled vocabulary from APA's Thesaurus of Psychological Index Terms®.