Samuel Richardson (1755). “A collection of the moral and instructive sentiments, maxims, cautions, and reflexions, contained in the histories of Pamela, Clarissa, and Sir Charles Grandison: Digested under proper heads, with references to the volume, ...”, p.380
Canada Month, June 1963. A later satirical version of this saying added to the end "Luckily, this is not difficult" (Paul Dickson, The Official Rules [1978]). See Eleanor Roosevelt 2
Joan Rivers' remarks on BBC 2 (February 23, 1990), as quoted in Elaine Bernstein Partnow "The Quotable Jewish Woman: Wisdom, Inspiration and Humor from the Mind and Heart" (p. 179), April 2004.
Oscar Wilde, Russell Jackson, Joseph Bristow, Ian Small (2000). “The Complete Works of Oscar Wilde: The picture of Dorian Gray : the 1890 and 1891 texts”, p.175, Oxford University Press on Demand