John Adams, Charles Francis Adams (1856). “The Works of John Adams, Second President of the United States: With a Life of the Author, Notes and Illustrations”, p.229
Allen Klein (1989). “The Healing Power of Humor: Techniques for Getting Through Loss, Setbacks, Upsets, Disappointments, Difficulties, Trials, Tribulations, and All that Not-so-funny Stuff”, Tarcher
Sir William Petty (1769). “Tracts, Chiefly Relating to Ireland: Containing: 1. A Treatise of Taxes and Contributions. II. Essays in Political Arithmetic. III. The Political Anatomy of Ireland”, p.219
John Adams, Charles Francis Adams (1856). “The Works of John Adams, Second President of the United States: With a Life of the Author, Notes and Illustrations”, p.229