1. Green, J. A.: On the number of automorphisms of a finite group. Proc. Roy. Soc. A237, 574?581 (1956).
2. Schur, I.: Über die Darstellung der endlichen Gruppen durch gebrochene lineare Substitutionen. J. reine angew. Math.127, 20?50 (1904).
3. Lyndon, R. C.: The cohomology of group extensions. Duke Math. J.15, 271?292 (1948).
4. Wiegold, J.: Groups with boundedly finite classes of conjugate elements. Proc. Roy. Soc. A238, 389?401 (1956).
5. Moran, S.: Associative operations on groups 1. Proc. London Math. Soc. (3)6, 581?596 (1956).