Jonathan M.; Bortolotti, Gary R. The bald eagle : haunts and habits of a wilderness monarch. Internet Archive. Washington : Smithsonian Institution Press
Fletcher, 85; hiking icon's books inspired generations to journey into the wilderness. Los Angeles Times. 16 June 2007 [9 January 2018]. ISSN 0458-3035 (美国英语)
(原始内容存档于2011-05-20) (英语). Linklater, Andro. Measuring America: How an Untamed Wilderness Shaped the United States and Fulfilled the Promise of Democracy. Walker