
" The Yellowstone National Park http://books.google.com/books?id=smQCAAAAIAAJ&pg=PA509", The Atlantic Monthly, volume LXXXI, number 486 (April 1898) pages 509-522 (at pages 515-516); modified slightly and reprinted in Our National Parks http://www.sierraclub.org/john_muir_exhibit/writings/our_national_parks/ (1901), chapter 2: The Yellowstone National Park
1900s, Our National Parks (1901)