zbMATH"Zentralblatt MATH (zbMATH) is the world’s most comprehensive and longest-running abstracting and reviewing service in pure and applied mathematics. It is edited by the European Mathematical Society (EMS), the Heidelberg Academy of Sciences and Humanities and FIZ Karlsruhe. The zbMATH database contains about 4 million bibliographic entries with reviews or abstracts currently drawn from about 3,000 journals and book series, and 180,000 books. The coverage starts in the 18th century and is complete from 1868 to the present by the integration of the "Jahrbuch über die Fortschritte der Mathematik" database." The classification system was updated in 2020. Argonne does not have a subscription to this database. However, the first 3 records in a search result are viewable to unregistered users. This can be very useful in verifying European/Asian based citations. Also includes the Mathematics Subject Classification (MSC) - a classification scheme maintained by Mathematical Reviews and zbMATH. It is used by these reviewing services and many others to categorize items in the mathematical sciences literature.