"Collected Papers: Toward a general social science" (1974) by Kenneth Boulding (p. 87), as quoted in "Environment, technology, and future generations" by D. A. Bella, 1978.
Benjamin Franklin, Ulysses S Grant, Andrew Carnegie, Henry Adams (2016). “Great American Lives: The Autobiography of Benjamin Franklin, Personal Memoirs of Ulysses S. Grant, Autobiography of Andrew Carnegie, and The Education of Henry Adams”, p.1685, Open Road Media