"New Studies in Philosophy, Politics, Economics and the History of Ideas". Book by Friedrich Hayek. Part I: "Philosophy ". Chapter 2: "The Pretence of Knowledge", p. 23, 1978.
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
Robert Browning, Elizabeth Barrett Browning (2009). “The Letters of Robert Browning and Elizabeth Barrett Browning: 1845-1846”, p.181, The Floating Press