Richard Courant in: The Parsimonious Universe, Stefan Hildebrandt & Anthony Tromba, Springer-Verlag, 1996, page 148
Famous Richard Courant Quotes
Richard Courant, "Mathematics in the Modern World", Scientific American, Vol 211, (Sep 1964), p. 42
Richard Courant, What is Mathematics?, (1941) p. xix
Richard Courant in: The Australian Mathematics Teacher, Volumes 39-40 http://books.google.co.in/books?id=CofxAAAAMAAJ, Australian Association of Mathematics Teachers, 1983, p. 3