^Peel, M. C.; Finlayson, B. L.; McMahon, T. A. (2007). "Updated world map of the Köppen−Geiger climate classification". Hydrol. Earth Syst. Sci. 11. ISSN1027-5606.
^Randy Moore and Kara Felicia Witt, The Grand Canyon: An Encyclopedia of Geography, History, and Culture, 2018, ABC-CLIO Publisher, p. 159.
^Harvey Butchart, Grand Canyon Treks 12,000 Miles Through the Grand Canyon, 1998, Spotted Dog Press, p. 131.
^Aaron Tomasi, Grand Canyon Summits Select An Obscure Compilation of Sixty-nine Remote Ascent Routes in the Grand Canyon National Park Backcountry, 2001, ISBN9780971088009, p. 47.
^N.H. Darton, Story of the Grand Canyon of Arizona, 1917, pp. 12, 62.
^William Kenneth Hamblin, Anatomy of the Grand Canyon: Panoramas of the Canyon's Geology, 2008, Grand Canyon Association Publisher, ISBN9781934656013.
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