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Zimmerman, Emily. "John Colter 1773?–1813". The Mountain Men: Pathfinders of the West 1810–1860. American Studies at the University of Virginia. Archived from the original on September 11, 2018. Retrieved May 8, 2007.
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Zimmerman, Emily. "John Colter 1773?–1813". The Mountain Men: Pathfinders of the West 1810–1860. American Studies at the University of Virginia. Archived from the original on September 11, 2018. Retrieved May 8, 2007.
Cook, Marshall. "Joel Estes Colorado Territory Exploration 1833-1834" Colorado Early Days, a manuscript written in the early 1880s presented by his daughter, Mrs H.A. Clingenpeel], Johnstown Co., September 1932, p.132
Estes Milton. "Memoirs of Estes Park" The Colorado Magazine, Vol XVI #4, July 1939 Estes
