1. J. B. Fraleigh, A First Course in Abstract Algebra, 4th. edition, Addison-Wesley, Reading, MA, 1989.
2. J. A. Gallian, Contemporary Abstract Algebra, 3rd. edition, D. C. Heath, Lexington, MA, 1994.
3. I. N. Herstein, Abstract Algebra, 2nd. edition, Macmillan, New York, NY, 1990.