[1]
T. Croft and R. Davison, Foundation maths, 5th ed. Harlow: Prentice Hall, 2010 [Online]. Available: http://www.vlebooks.com/vleweb/product/openreader?id=AberystUni&isbn=9780273729488
[2]
T. Croft and R. Davison, Foundation maths, 5th ed. Harlow: Pearson/Prentice Hall, 2010.
[3]
K. H. Rosen and K. Krithivasan, Discrete mathematics and its applications, 7th ed., Global ed. New York: McGraw-Hill, 2013.
[4]
L. Spector, ‘TheMathPage Skill in Algebra’. [Online]. Available: http://www.themathpage.com/alg/algebra.htm
