Bibliographical reference metadata. A way of indexing papers for reference. Subclasses of review databases identify the paper being reviewed and not the reviews, hence one may assert equivalence among classes beloging to different review indexes. Bibliographical Databases. Zentralblatt fuer Mathematik und ihre Grenzgebiete, the longest-term running abstracting and reviewing service in the field of mathematics published by Springer-Verlag and edited by the European Mathematical Society (EMS), Fachinformationszentrum (FIZ) Karlsruhe, and the Heidelberger Akademie der Wissenschaften. The Mathematical Reviews Database, database of bibliographic information and reviews created and maintained by the American Mathematical Society. Zentralblatt fuer Didaktik der Mathematik, International Reviews on Mathematical Education. The database CompuScience is part of the Project "FachInformationsSystem Informatik" (FIS-I) . Partners are the "Gesellschaft fuer Informatik" (GI), the universities of Karlsruhe, Munich and Trier. Digital archive of the most important mathematical publications of the period 1868-1942 and a database based on the "Jahrbuch ueber die Fortschritte der Mathematik" Zbl_0805.13007 MR1263871 Reference ID identifying an item in a bibliographical index