Liu, C. . L. (1968). Introduction to combinatorial mathematics. McGraw-Hill.
Cita Chicago (17th ed.)Liu, C L. Introduction to Combinatorial Mathematics. New York: McGraw-Hill, 1968.
Cita MLA (9th ed.)Liu, C L. Introduction to Combinatorial Mathematics. McGraw-Hill, 1968.
Atenció: Aquestes cites poden no estar 100% correctes.