(en) J. M. G. Gradidge, J.M. Davis et J.A. Whittle, The Douglas DC-3 and its predecessors, Tonbridge, Air-Britain (Historians, , 672 p. (ISBN978-0-85130-119-8, OCLC60066085), p. 254.
(en) J. M. G. Gradidge, J.M. Davis et J.A. Whittle, The Douglas DC-3 and its predecessors, Tonbridge, Air-Britain (Historians, , 672 p. (ISBN978-0-85130-119-8, OCLC60066085), p. 269 à 278.