H.K. Thomas, Diary, Dec. 17, 1870.
H.K. Thomas, Diary, Jan. 20, 1871.
H.K. Thomas, Diary, Aug. 21, 1871.
H.K. Thomas, Diary, April 28, 1871.
David A. Wolff, Industrializing the Rockies: Growth, Competition, and Turmoil in the Coalfields of Colorado and Wyoming, 1868-1914 (Boulder: Univ. of Colorado Press, 2003), 5-6, 21-22.