The articles are chosen from the periodicals, yearbooks and Festschriften available in the Institue. Since 1996, articles have been electronically cataloged and can be found in the OPAC. Thereafter, articles have been cataloged using a classification scheme for Public International Law (about 400 headings) and a uniform classification scheme for Municipal Law (about 50 headings).
Periodicals in English, French, German, Italian and Spanish are evaluated. American journals devoted primarely to domestic topics are no longer included in this process. Reference is made in this regard to the prevalent possibilities for online research.
Older articles (from 1955 to 1995 inclusive) are available on index cards, which are classified with subject headings. The card index lists approximately 408,000 articles.
OPAC entries under Public International Law are also used for the printed publication "Public International Law", which has appeared since 1975.