Boolean operators can limit or expand searches depending on which one is used.
Part A, Modern history abstracts, 1450-1914 and Historical abstracts. 3rd Floor Index Tables Historical Abstracts is the leading database for historical research at the PSU library. Historical Abstracts contains abstracts of articles, book reviews, and other materials from around the world, excluding the United States and Canada, from 1450 to the present. Historical Abstracts is also available in paper on the Third Floor. The Humanities Index is a print index that allows the user to find citations to journal articles within the humanities.