In Orbis, OPAC contains materials from 1977 to the present. For materials published prior to 1977 that do not appear in OPAC, check in the card catalog in Sterling Memorial Library. More than half of the Library collection is represented ONLY in the card catalog. Use these periodical indexes to locate articles in journals, monograph series, dissertations, etc. These indexes are not yet available through Orbis on the Web.
Every article is indexed.
The scope is international, including journals in English, French, German, Italian, Spanish and other Western languages. PCI Web currently indexes over six million articles in 1,595 journals. Every year, it adds records for more than two million more articles. It will grow to encompass 3,500 journals and fifteen million individual articles. Yale University Library.