Elbert Hubbard (2009). “Love, Life & Work: Being a Book of Opinions Reasonably Good-Natured Concerning How to Attain the Highest Happiness for One's Self with the Least Possible Harm to Others”, p.66, The Floating Press
William Wilberforce (1797). “A Practical View of the Prevailing Religious System of Professed Christians: In the Higher and Middle Classes in this Country, Contrasted with Real Christianity”, p.424