Henry Ward Beecher, Augusta Moore (1859). “Notes from Plymouth Pulpit: A Collection of Memorable Passages from the Discourses of Henry Ward Beecher, with a Sketch of Mr. Beecher and the Lecture Room”, p.57
Alan Greenspan's address to the Federal Reserve Bank of Chicago's Forty-first Annual Conference on Bank Structure in Chicago, Illinois, www.federalreserve.gov. May 5, 2005.
Henry David Thoreau (2017). “Journeys, Adventures & Life in Harmony with Nature – 6 Book Collection (Illustrated): Including Walden, A Week on the Concord and Merrimack Rivers, The Maine Woods, Cape Cod, A Yankee in Canada & Canoeing in the Wilderness - North American Highlands Series”, p.270, e-artnow