1. N. Alon: Covering graphs by the minimum number of equivalence relations.Combinatorica,6 (3) (1986), 201?206.
2. M. S. Chung, andD. B. West: Thep-intersection number of a complete bipartite graph and orthogonal double coverings of a clique, to appear.
3. N. Eaton, R. Gould, andV. R�dl: Onp-intersection representations, to appear.
4. P. Erd?s, A.W. Goodman, andL. P�sa: The representation of a graph by set intersections,Canad. J. of Math. 18 (1966), 106?112.
5. P. Erd?s andL. Lov�sz: Problems and results on 4-chromatic hypergraphs and some related questions, In:Colloquia Mathematica Societatis J�nos Bolyai, 10. Infinite and Finite Sets, Vol. II., North-Holland Publishing, 1975.