Henry Margenau, Roy Abraham Varghese (1992). “Cosmos, Bios, Theos: Scientists Reflect on Science, God, and the Origins of the Universe, Life, and Homo Sapiens”, p.62, Open Court Publishing
Sir Humphry Davy (1840). “Salmonia: or, Days of fly-fishing; in a series of conversations: with some account of the habits of fishes belonging to the genus Salmo. Consolation in travel, or, The last days of a philosopher”, p.351