1. Design Theory;Beth,1985
2. Combinatorial designs and related systems;Bridges;J. Algebra,1969
3. Primes in the semigroup of Boolean matrices;de Caen;Linear Algebra Appl.,1981
4. On the decomposition of directed graphs into complete bipartite subgraphs;de Caen;Ars Combin.,1987
5. Enumeration of symmetric designs (25, 9, 3);Denniston;Ann. Discrete Math.,1982