International Standard Musical Work Code (ISWC)
(international standard) The internationally recognized standard numbering system for the identification of musical works. An ISWC for musical works consists of a letter followed by nine digits and a check digit, as follows:
distinguishing element (1 letter); work identifier (9 digits) and check digit (1 digit). The distinguishing element for musical works is the letter «T». In printed form the ISWC is preceded by a label and may include hyphens and dots between the elements for ease of reading. Example ISWC T-034.524.680-1
Arrangements, adaptations and translations are all given separate ISWCs. These are known collectively as versions. The system is based on the International Standards Organization ISO 15707. The International ISWC Agency is provided by CISAC (International Confederation of Societies of Authors and Composers).
Numbers may be obtained through rights societies or directly by individuals. Works in the public domain may also have a number allocated.
Contact: ISWC Administrator; International ISWC Agency; CISAC; 20-26, Boulevard du Parc; 92200 Neuilly sur Seine France; Tel:  1 55 62 08 50; Web: www.iswc.org.