Summary of Radiometric age Determinations on Mesozoic and Cenozoic Igneous Rocks and Uranium and Base Metal Deposits in Colorado, Dec. 1974, Box: 7, Folder: 7. J. Harlan Johnson papers, RH MS 735. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/52830 Accessed January 12, 2025.