1. On groups without abelian composition factors;Bercov;J. Algebra,1967
2. Complements of normal subgroups in infinite groups;Dixon,1967
3. Zur Erweiterungstheorie der endlichen Gruppen;Gaschütz;J. Reine Angew. Math.,1952
4. Cohomological Topics in Group Theory;Gruenberg,1970
5. Endliche Gruppen I;Huppert,1967