Identification of tree species on large-scale panchromatic and color aerial photographs / by R.C. Heller, G.E. Doverspike, and R.C. Aldrich. - Heller, Robert Chester, 1918-; Doverspike, G. E.; Aldrich, Robert Clement, 1922- (Washington, D.C. : U.S. Dept. of Agriculture, Forest Service, 1964)
Bibliography: p. 15.
Keywords: Aerial photography in forestry; Photographic interpretation; Trees -- Minnesota -- Ely -- Identification