Note 6 — Chapter XII · MAPPING AND CHARTING FROM THE AIR (Figs. 54 to 82)
Reading edition
The Use of Aerial Photographs in Topographic Mapping: A Report of the Committee on Photographic Surveying of the Board of Surveys and Maps of the Federal Government, 1920, Air Service Information Circular (Aviation) No. 184, War Department, Washington, D. C., 1921.