The following sources were widely used in compiling this document:
 Field Artillery Gunnery FM6-40, Department of the [US] Army, January 1950.
This is the primary source of this material except where otherwise marked.
 David Wesely's comments and handouts from a talk on artillery at Origins'96. [Highly recommended.]
 Handbook on German Military Forces, TM-E30-451, US War Dept, March 1945
 Handbook on USSR Military Forces, TM30-430, US War Dept, Nov 1945
 Handbook on Japanese Military Forces, TM-E30-480, US War Dept, Oct 1944