Letter to "The Keicomolo" - Kleiner, Cole, and Moe (October 1916), in "Selected Letters I, 1911-1924" edited by August Derleth and Donald Wandrei, (p. 27), 1964.
"Minima Moralia: Reflexionen aus dem beschadigten Leben (Minima Moralia: Reflections From Damaged Life)". Book by Theodor Adorno (1951) translated by E. Jephcott (§ 1), 1974.