Cameron, Peter J. Introduction to Algebra. 2nd ed, vol. Oxford mathematics, 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.
Ledermann, Walter and Weir, Alan J. Introduction to Group Theory. 2nd ed, vol. Longman mathematics series, Longman, 1996.