Zeller, H. D.; Soister, Paul E. & Hyden, Harold Julius. Progress Report on the Geology and Uranium Deposits of the Gas Hills Area, Fremont and Natrona Counties, Wyoming, report, September 1955; (https://digital.library.unt.edu/ark:/67531/metadc304641/m1/17/: accessed February 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .