Browning Machine Guns, Caliber .30 inch, M1917A1, M1919A4, and M1919A6 - USA Voorschrift, Field Manual, 23-55 Machine Gun Handbook. (Technical). Volume I, Pamphlet no. 1. Vickers.303 inch and 5 inch Machine Guns and Appurtenances. WO 888 - Engeland Voorschrift 26/Publications/3431
