NATIONAL GEOGRAPHIC SOCIETY, WASHINGTON, D. C.
National Geographic Society: U. S. Army Air Corps stratosphere flight of 1935 in the balloon Explorer II.
NATIONAL GEOGRAPHIC SOCIETY, WASHINGTON, D. C. National Geographic Society: U. S. Army Air Corps stratosphere flight of 1935 in the balloon Explorer II. © 7Jan37; A103275. National Geographic Society (PWH); 15May64; R337779.
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