1. Elements of Mathematics, Commutative Algebra;Bourbaki,1972
2. Topics in Geometric Group Theory;de la Harpe,2000
3. Character Theory of Finite Groups;Isaacs,1976
4. Basic Algebra II;Jacobson,1980
5. Non-abelian groups in which every subgroup is abelian;Miller;Trans. Amer. Math. Soc.,1903