1. A perfect group of order 8, 315, 553, 613, 086, 720, 000;Conway;Bull. London Math. Soc.,1969
2. A simple group of order 44, 352, 000;Higman;Math. Z.,1968
3. On the simple group of D. G. Higman and C. C. Sims;Higman;Ill. J. Math.,1969
4. On t-designs and groups;Hughes;Amer. J. Math.,1965
5. Transitive Erweiterungen endlicher Permutationsgruppen;Luneburg;Springer Lecture Notes in Mathematics,1969