Wigdor, E.I. Report No. PAS-4, Strength Tests of Stressed-Skin Structures (Aircraft Floats). Ottawa, NRC, July 1937. Two volumes, 8.5x11", illus, hard-bound in buckram, x-libris University of Detroit with usual stamps and paste-ons. Vol 1: 200pp mimeo plus graphs, 30 original 8x10-size b&w photos of damage to floats; Vol 2: 8pp + graphs and 10 8x10 size b&w photos of float damage. Assumed a very small publication run because of the original photos bound in. Good condition for x-library copies.