Albert Einstein, Stephen W. Hawking (2007). “A Stubbornly Persistent Illusion: The Essential Scientific Works of Albert Einstein”, p.249, Running Press
Quoted in Alexander Macfarlane, Ten British Mathematicians of the Nineteenth Century (1916). "Pure mathematics; may it never be of use to any man!" is cited as the toast of the Mathematical Society of England in Science, 10 Dec. 1886.
Albert Einstein (2015). “Bite-Size Einstein: Quotations on Just About Everything from the Greatest Mind of the Twentieth Century”, p.32, St. Martin's Press