Finite analogues of non-Euclidean spaces and Ramanujan graphs.

Eiichi Bannai Osamu Shimabukuro Hajime Tanaka Finite analogues of non-Euclidean spaces and Ramanujan graphs. 243-259 2004 25 Eur. J. Comb. 2 http://dx.doi.org/10.1016/S0195-6698(03)00110-0 db/journals/ejc/ejc25.html#BannaiST04