Albert Einstein, Stephen W. Hawking (2007). “A Stubbornly Persistent Illusion: The Essential Scientific Works of Albert Einstein”, p.346, Running Press
Albert Einstein, Stephen W. Hawking (2007). “A Stubbornly Persistent Illusion: The Essential Scientific Works of Albert Einstein”, p.346, Running Press
Albert Einstein (2015). “Bite-Size Einstein: Quotations on Just About Everything from the Greatest Mind of the Twentieth Century”, p.20, St. Martin's Press