Fisher, A. K.; Stejneger, Leonhard; Gilbert, Charles H.; Riley, C. V.; Stearns, R. E. C.; Merriam, C. Hart et al. The Death Valley Expedition: A Biological Survey of Parts of California, Nevada, Arizona, and Utah, Part 2, report, May 31, 1893; (https://digital.library.unt.edu/ark:/67531/metadc700948/m1/1/: accessed December 16, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .