Ash, C., McEliece, R. J., & Ash, R. B. (1989). Introduction to Discrete Mathematics. Random House.[br][br][i]Book of Proof[/i]. (2018, February 14).[br]Virginia Commonwealth University. Retrieved July 2, 2023, from[br]https://www.people.vcu.edu/~rhammack/BookOfProof/Main.pdf#page=15