1.
Cameron, Peter J. Introduction to Algebra. Vol Oxford mathematics. 2nd ed. Oxford University Press; 2008. http://ezproxy.library.qmul.ac.uk/login?url=http://www.vlebooks.com/vleweb/product/openreader?id=QMUL&isbn=9780191566226&uid=^u
2.
Ledermann, Walter, Weir, Alan J. Introduction to Group Theory. Vol Longman mathematics series. 2nd ed. Longman; 1996.