John Muir Quotes about Wall
John Muir, Peter Browning (1988). “John Muir, in His Own Words: A Book of Quotations”, p.16, Great West Books
John Muir (1973). “The American Wilderness: In the Words of John Muir”
John Muir (2017). “The Yosemite: John Muir's quest to preserve the wilderness”, p.11, Vertebrate Publishing
John Muir (2015). “John Muir’s Incredible Travel Memoirs: A Thousand-Mile Walk to the Gulf, My First Summer in the Sierra, The Mountains of California, Travels in Alaska, Steep Trails… (Illustrated): Adventure Memoirs & Wilderness Studies from the Naturalist, Environmental Philosopher and Early Advocate of Preservation of Wilderness, the Author of The Yosemite and Picturesque California”, p.38, e-artnow