90XX OPERATIONS RESEARCH, MATHEMATICAL PROGRAMMING
 9000 General reference works (handbooks, dictionaries, bibliographies, etc.)
 9001 Instructional exposition (textbooks, tutorial papers, etc.)
 9002 Research exposition (monographs, survey articles)
 9003 Historical (must also be assigned at least one classification number from Section 01)
 9004 Explicit machine computation and programs (not the theory of computation or programming)
 9006 Proceedings, conferences, collections, etc.
 9008 Computational methods

90Bxx Operations research and management science
(7)

90Cxx Mathematical programming [See also 49Mxx, 65Kxx]
(10)