Report upon United States Geographical surveys west of the on...
A. A. Humphreys, chief of engineers until June 1879. Succeeded by H. G. Wright. Date of publication for vol. 2. Astronomy and barometric hypsometry: 1877 (t.p.) Available also through the Library of Congress Web site as a raster image. Form AACR2: ga10 2004-03-02
Geographical Surveys West of the 100th Meridian (U.S.) - Wheeler, George M. (George Montague) - Humphreys, A. A. (Andrew Atkinson) - Wright, Horatio Gouverneur