API MPMS chapters covering petroleum measurement.
API identifiers follow: API [Type] [Number]. Types include Std (Standard), RP (Recommended Practice), Spec (Specification), TR (Technical Report), Bull (Bulletin), Publ (Publication), MPMS (Manual of Petroleum Measurement Standards).
API Manual of Petroleum Measurement Standards identifiers are composed of these elements:
API
APIStd, RP, Spec, TR, Bull, Publ, MPMS, COS
RPThe document number
500