[1]  Shemetkov L A, Skiba A N. Formations of Algebraic Systems. Moscow: Nauka, 1989

[2]  Guo W. The Theory of Classes of Groups. Beijing-New York-Dordrecht-Boston-London: Science Press-Kluwer Academic Publishers, 2000

[3]  Xu M. A Introduction to Finite Groups. Beijing: Science Press, 1999 (In Chinese)

[4]  Lam C, Shum K P, Guo W. Generalized Ito's theorem on p-nilpotent groups. Pure Mathematics and Applications, 2000, 11: 593--596

[5]  Buckley J. Finite groups whose minimal subgroups are normal. Math Z, 1970, 15: 15--17

[6]  Ramadan M. Influence of normality on maximal subgroups of Sylow subgroups of a finite group. Acta Math Hungar, 1992, 59(1/2): 107--110

[7]  Al-Sharo Kh A, Molokova E A, Shemetkov L A. Factorizable groups and formations. Acta Applicandae Mathematicae, 2005, 85: 3--10

[8]  Al-Sharo Kh A, Shemetkov L A. On subgroups of prime order in a finite group. Ukr Math J, 2002, 54(6): 915--923

[9]  Al-Sharo Kh A, Shemetkova O L. An application of the concept of a generalized central element. Algebra and Discrete Math, 2007, (4): 1--10

[10]  Guo W. The influence of minimal subgroups on the structure of finite groups. Southeast Asia Bulletin of Mathematics, 1998, 22: 287--290

[11]  Guo W. Finite groups with nipotent local subgroups. Chinese Annals of Mathematics, 2004, 25A: 217--224

[12]  Shemetkova O L. Finite groups with a system of generalized central elements. Algebra and Discrete Math, 2004, (4): 59--71

[13]  Shemetkova O L. On finite groups with Q-central elements of prime order. Proc of the Institute of Mathematics, Minsk, Republic of Belarus, 2008, 16(1): 97--99

[14]  Arad Z, Fisman E. On finite factorizable groups. J Algebra, 1984, 86: 522--548

[15] Robinson D J S. A Course in the Theory of Groups. New York-Heidelberg-Berlin: Springer-verlag, 1982