1. On non-strictly simple groups;Hall, P.;Proc. Cambridge Philos. Soc.,1963
2. On the theory of generalized solvable and generalized nilpotent groups;Merzljakov, Ju. I.;Algebra i Logika Sem.,1963
3. Radical groups;Plotkin, B. I.;Amer. Math. Soc. Transl. (2),1961