David Lavender, The Great Persuader: The Biography of Collis P. Huntington (Niwot: Univ. Press of Colorado, 1998, orig. ed., 1969), 105-7.
"An Act to aid in the construction of a railroad and telegraph line from the Missouri river to the Pacific ocean, and to secure to the government the use of the same for postal, military, and other purposes,"; Act of July 1, 1862, Statutes at Large 12 (1863): 489.
Klein, Union Pacific, 22-67
Nathaniel Hawthorne, "Chiefly about War Matters," Atlantic Monthly, July 1862, pp. 59-60.
http://www.cr.nps.gov/nr/travel/wash/dc36.htm.
Bain, Empire Express, 178-80.
Klein, Union Pacific, 32-33.
Maury Klein gives a much fuller account of the various interests involved and the maneuvering behind the act, Klein, Union Pacific, 26-33.
Hopkins to CPH, Feb. 16, 1864, CPH Papers, ser. 1, r. 1.