Ulam, S. M. (1964). Problems in modern mathematics. John Wiley & Sons.
Cita Chicago (17th ed.)Ulam, S. M. Problems in Modern Mathematics. Nueva York: John Wiley & Sons, 1964.
Cita MLA (9th ed.)Ulam, S. M. Problems in Modern Mathematics. John Wiley & Sons, 1964.
Atenció: Aquestes cites poden no estar 100% correctes.