Albert Einstein (2015). “Bite-Size Einstein: Quotations on Just About Everything from the Greatest Mind of the Twentieth Century”, p.53, St. Martin's Press
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
In a letter to his cousin and second wife Elsa, during a visit to the University of Oxford, in collection donated to the Hebrew University of Jerusalem in Israel by Einstein's stepdaughter Margot, as quoted in "Einstein in no-sock shock", New Scientist, July 15, 2006.