1983API PUBL 2564-1983 Manual of Petroleum Measurement Standards Chapter 15 - Guidelines for the Use of the International System of Units (SI) in the Petroleum and Allied Industries (SECOND EDITION)
1974API PUBL 2564-1974 Manual of Petroleum Measurement Standards Chapter 15 – Section 2 Conversion of Operational and Process Measurement Units to the Metric (SI) System (First Edition; Includes ERTA)