The Discovery of Yellowstone Park : Journal of the Washburn Expedition to the Yellowstone and Firehole Rivers in the Year 1870 [electronic resource] /
Nathaniel Pitt Langford
- Project Gutenberg, 2004
- Project Gutenberg 11145 .
Public domain in the USA.
Electronic text
Yellowstone National Park -- Discovery and exploration Langford, Nathaniel Pitt, 1832-1911 -- Diaries