[en] [Gutenberg 7091] • The Yosemite Vertebrate Digital
[en] [Gutenberg 29681] • A Mountain Boyhood Bison Books
[en] [Gutenberg 42030] • The Rocky Mountain Wonderland University of Nebraska Press
[en] [Gutenberg 28562] • Wild Life on the Rockies University of Nebraska Press
[en] [Gutenberg 50381] • Colter's Hell and Jackson's Hole / The Fur Trappers' Exploration of the Yellowstone and Grand Teton Park Region Yellowstone Library and Museum Association
[en] [Gutenberg 61114] • Westy Martin in the Yellowstone Grosset & Dunlap
[en] [Gutenberg 30924] • Thirty-Seven Days of Peril / from Scribner's Monthly Vol III Nov. 1871 University of Utah Press
[en] [Gutenberg 52532] • Saguaro National Monument, Arizona Forgotten Books
[en] [Gutenberg 60131] • Estes Park, Colorado iOnlineShopping.com
[en] [Gutenberg 42112] • The Yellowstone National Park: Historical and Descriptive University of Oklahoma Press
[en] [Gutenberg 46305] • Yellowstone via Gallatin Gateway Montana Project Gutenberg