Ballester-Bolinches, A.; Kamornikov, S. F.; Pedraza Aguilera, María Carmen; Pérez-Calabuig, V.(Springer-Verlag, 2020-03-02)
[EN] Let sigma = {sigma(i) : i is an element of I} be a partition of the set P of all prime numbers. A subgroup X of a finite group G is called sigma-subnormal in G if there is a chain of subgroups
X = X-0 subset of X-1 ...