Operator's manual for Army U-21A aircraft.
APA Citation
United States. Department of the Army. (1989). Operator's manual for Army U-21A aircraft. [Washington, D.C.]: Headquarters, Dept. of the Army.
MLA Citation
United States. Department of the Army. Operator's Manual for Army U-21A Aircraft. [Washington, D.C.]: Headquarters, Dept. of the Army, 1989.
Warning: These citations may not always be complete (especially for serials).