1. Sur une conjecture relative au probléme des codes optimaux;Berge;Comm. 13ème assemblée générale de l'URSI, Tokyo,1962
2. Graphical properties related to minimal imperfection;Bland;Discrete Math.,1979
3. Graph Theory with Applications;Bondy,1976
4. On generalized graph colorings;Brown;J. Graph Theory,1987
5. The complexity of i-perfect graph recognition;Cai,1990