Velleman, D. J. (2006). How to prove it: A structured approach (2nd ed.). Cambridge University Press.

Velleman, Daniel J. How to Prove It: A Structured Approach. 2nd ed. Cambridge ; New York: Cambridge University Press, 2006.

Velleman, Daniel J. How to Prove It: A Structured Approach. 2nd ed. Cambridge University Press, 2006.