1. Vasil’ev A. F. and Kamornikov S. F., “On the functorial method for studying the lattices of subgroups of finite groups,” Siberian Math. J., 42, No. 1, 25–33 (2001).
2. Barnes D. W. and Kegel O. H., “Gaschütz functors on finite soluble groups,” Math. Z., Bd 94, Heft 2. S. 134–142 (1966).
3. Sudbrock W., “Sylowfunktionen in endlichen Gruppen,” Rend. Semin. Mat. Univ. Padova, 36, No. 1, 158–184 (1966).
4. Mann A., “On subgroups of finite soluble groups. III,” Israel J. Math., 16, No. 4, 446–451 (1973).
5. Skiba A. N., Algebra of Formations [in Russian], Belarusskaya Nauka, Minsk (1977).