1
Croft T, Davison R. Foundation maths. 5th ed. Harlow: : Prentice Hall 2010. http://www.vlebooks.com/vleweb/product/openreader?id=AberystUni&isbn=9780273729488
2
Croft T, Davison R. Foundation maths. 5th ed. Harlow: : Pearson/Prentice Hall 2010.
3
Rosen KH, Krithivasan K. Discrete mathematics and its applications. 7th ed., Global ed. New York: : McGraw-Hill 2013.