(OPO publication 4.) [Restricted. Processed. Text on p. 2 of cover. Supersedes confidential memorandum dated Apr. 1, 1943, Classification of aerial photography.]
Notes:
(OPO publication 4.) [Restricted. Processed. Text on p. 2 of cover. Supersedes confidential memorandum dated Apr. 1, 1943, Classification of aerial photography.]