1. On Moore graphs;Bannai;J. Fac. Sci. Univ. Tokyo Sect. I A, Math.,1973
2. Algebraic Graph Theory;Biggs,1974
3. Extremal Graph Theory;Bollobás,1978
4. On Moore graphs;Damerell;Proc. Cambridge Philos. Soc.,1973
5. On eigenvalues and colorings of graphs;Hoffman,1970