1. Hypergraphs: Combinatorics of Finite Sets;Berge,1989
2. Interval Hypergraphs;Rosenberg,1989
3. The mixed hypergraphs;Voloshin;Comput. Sci. J. Moldova,1993
4. On the upper chromatic number of a hypergraph;Voloshin;Australasian J. Combin.,1995
5. Numarul chromatic superior al hipergrafurilor intervale mixte;Voloshin,1995