Robert H. Schuller (1993). “Robert H Schuller: The Inspirational Writings : Tough Times Never Last, But Tough People Do/Tough Minded Faith for Tender Hearted People”, Bbs Publishing Corporation
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.698, e-artnow