80-00 General reference works (handbooks, dictionaries, bibliographies, etc.)
80-01 Instructional exposition (textbooks, tutorial papers, etc.)
80-02 Research exposition (monographs, survey articles)
80-03 Historical (must also be assigned at least one classification number from Section 01)
80-04 Explicit machine computation and programs (not the theory of computation or programming)
80-05 Experimental work
80-06 Proceedings, conferences, collections, etc.
80Axx Thermodynamics and heat transfer
80Mxx Basic methods