1. F.E. Bennett and N.S. Mendelsohn, On the existence of extended triple systems, Utilitas Math. (to appear).
2. On the construction of balanced incomplete block designs;Bose;Ann. Eugenics,1939
3. Extended triple systems;Johnson;Aequationes Math.,1972
4. A natural generalization of Steiner triple systems;Mendelsohn,1971
5. Orthogonal Steiner systems;Mendelsohn;Aequationes Math.,1970