Liu, C. (1985). Elements of Discrete Mathematics (2nd.).
Cita Chicago (17th ed.)Liu, C.L. Elements of Discrete Mathematics. 2nd. McGraw Hill Book Company, 1985.
Cita MLA (9th ed.)Liu, C.L. Elements of Discrete Mathematics. 2nd. 1985.
Atenció: Aquestes cites poden no estar 100% correctes.