Operator's manual for Army RU-21A and RU-21D aircraft.

"29 October 1982."

Aviation unit and aviation intermediate maintenance manual : Army models U-21A, RU-21A, and RU-21D.

"31 December 1976"--Vol. 1.

Operator's and crewmember's checklist : Army models RU-21A and RU-21D aircraft : pilot's checklist.

"3 September 1982."