“Attributed to Hopper, without source, in The UNIX-HATERS Handbook (1994), edited by Simson Garfinkel, Daniel Weise, and Steven Strassmann , p. 9, this is most commonly attributed to Andrew Tanenbaum, as it appears in his book Computer Networks (1981), p. 168, but has also been attributed to Patricia Seybold and Ken Olsen.”

Source: Wikiquote