John Muir (2015). “STEEP TRAILS: California - Utah - Nevada - Washington - Oregon - The Grand Canyon: Adventure Memoirs, Travel Sketches, Nature Essays and Wilderness Studies from the author of The Yosemite, Our National Parks, A Thousand-mile Walk to the Gulf & Picturesque California”, p.45, e-artnow
John Muir (2015). “JOHN MUIR’S CALIFORNIA COLLECTION: My First Summer in the Sierra, Picturesque California, The Mountains of California, The Yosemite & Our National Parks (Illustrated): Adventure Memoirs, Travel Sketches, Nature Writings and Wilderness Essays”, p.234, e-artnow
John Muir (2015). “STEEP TRAILS: California - Utah - Nevada - Washington - Oregon - The Grand Canyon: Adventure Memoirs, Travel Sketches, Nature Essays and Wilderness Studies from the author of The Yosemite, Our National Parks, A Thousand-mile Walk to the Gulf & Picturesque California”, p.45, e-artnow