"The Superinvestors of Graham-and-Doddsville". Essay by Warren Buffett published in Hermes, the Columbia Business School Magazine (1984), later quoted in "31 years ago, Warren Buffett revealed the secret to investing and correctly predicted nobody would listen" by Myles Udland, www.businessinsider.com. August 24, 2015.
Lawrence A. Cunningham, Warren E. Buffett (2013). “The Essays of Warren Buffett: Lessons for Corporate America (Third Edition)”, p.63, Carolina Academic Press