1. W. Guo, The Theory of Classes of Groups, Math. Appl. Dordrecht, 505, Kluwer, Dordrecht (2000).
2. B. Huppert, Endliche Gruppen, Vol. 1, Grundlehren Math. Wiss., 134, Springer, Berlin (1979).
3. T. Foguel, “On seminormal subgroups,” J. Alg., 165, No. 3, 633-635 (1994).
4. X. Su, “Seminormal subgroups of finite groups,” J. Math., Wuhan Univ., 8, No. 1, 5-10 (1988).
5. A. Ballester-Bolinches and M. C. Pedraza-Aguilera, “Sufficient conditions for supersolubility of finite groups,” J. Pure Appl. Alg., 127, No. 2, 113-118 (1998).