Proof

•\say
How to Prove It by Daniel J. Velleman

•\say
Book of Proof by Richard Hammack freely available online (subject to licensing conditions) at https://www.people.vcu.edu/~rhammack/BookOfProof/
How to Prove It by Daniel J. Velleman
Book of Proof by Richard Hammack freely available online (subject to licensing conditions) at https://www.people.vcu.edu/~rhammack/BookOfProof/