Séminaire Lotharingien de Combinatoire, B20e (1988), 12 pp.
[Formerly: Publ. I.R.M.A. Strasbourg, 1988, 372/S-20, p. 87-99.]
A rational congruence for a standard orbit decomposition
We consider the orbit decomposition given by a standard automorphism
group of a point-divisible design (SRGDD in Bose and Connor 
terminology), and we exhibit a rational congruence naturally associated
to this decomposition.
 R.C. Bose and W.S. Connor, Combinatorial properties of group divisible
incomplete block designs, Ann. Math. Statist., vol. 23, 1952,
Dipartimentico di Matematica, Università
La Sapienza, I-00185 Roma
The paper has been finally published under the same title in
European J. Combin. 11 (1990), 105-113.