Velleman, D. J. (2006). How to prove it: A structured approach (2nd ed.). Cambridge University Press.
Cita Chicago (17th ed.)Velleman, Daniel J. How to Prove It: A Structured Approach. 2nd ed. Cambridge ; New York: Cambridge University Press, 2006.
Cita MLA (8th ed.)Velleman, Daniel J. How to Prove It: A Structured Approach. 2nd ed. Cambridge University Press, 2006.
Atenció: Aquestes cites poden no estar 100% correctes.