Links to pages on normal subgroups:
(1) http://mathworld.wolfram.com/NormalSubgroup.html
(2) http://eom.springer.de/N/n067690.htm
(3) http://www.math.uiuc.edu/~r-ash/Algebra/Chapter1.pdf
(4) http://math.ucr.edu/home/baez/normal.html
References:
- Dummit, D.S. & Foote, R.M. (1991). Abstract Algebra. United States: Prentice Hall.
- Gallian, J.A. (2010). Contemporary Abstract Algebra. United States: Brooks/Cole.
- MA 453 lecture notes, Professor Uli Walther
