@book{Croft_Davison_2010a, address={Harlow}, edition={5th ed}, title={Foundation maths}, url={http://www.vlebooks.com/vleweb/product/openreader?id=AberystUni&isbn=9780273729488}, publisher={Prentice Hall}, author={Croft, Tony and Davison, Robert}, year={2010} }
@book{Croft_Davison_2010b, address={Harlow}, edition={5th ed}, title={Foundation maths}, publisher={Pearson/Prentice Hall}, author={Croft, Tony and Davison, Robert}, year={2010} }
@book{Rosen_Krithivasan_2013, address={New York}, edition={7th ed., Global ed}, title={Discrete mathematics and its applications}, publisher={McGraw-Hill}, author={Rosen, Kenneth H. and Krithivasan, Kamala}, year={2013} }
@misc{Spector, title={TheMathPage Skill in Algebra}, url={http://www.themathpage.com/alg/algebra.htm}, author={Spector, Lawrence} }
