John Muir (1997). “Nature Writings: The Story of My Boyhood and Youth, My First Summer in the Sierra, the Mountains of California, Stickeen, Selected Essays”, p.517, Library of America
Robert E. Howard (2016). “CONAN THE BARBARIAN SERIES – Complete Collection (Fantasy & Action-Adventure Classics): Pre-historic world of dark magic and savagery - 20 books about the Cimmerian Barbarian, Thief, Pirate and Eventual King of Aquilonia During the pre-Ice Age, Hyborian Age, Featuring a Poem and an Essay”, p.192, e-artnow
John Muir (1997). “Nature Writings: The Story of My Boyhood and Youth, My First Summer in the Sierra, the Mountains of California, Stickeen, Selected Essays”, p.225, Library of America