CPH to Gates, July 12, 1887, CPH Papers, ser. 1, r. 45.
CPH to Friend Stanford, July 13, 1887, CPH Papers, ser. 1, r. 45.
CPH to Gates, July 30, 1887, CPH Papers, ser. 1, r. 45.
Pierpont Morgan to CPH, Nov. 29, 1887, CPH Papers, ser. 1, r. 46.
C. Crocker to CPH, Feb. 3, 1888, CPH Papers, ser. 1, r. 46.
C. Crocker to CPH, Jan. 18, 1889, CPH Papers, ser. 1, r. 47.
Stuart Daggett, Chapters on the History of the Southern Pacific (New York: A. M. Kelley, 1966, orig. ed. 1922), 136-38.
Mahl, Memoirs: P.I. Co., G18, Mahl Papers.