1. Eigenvalues and expanders;Alon;Combinatorica,1986
2. Finite Upper Half Planes over Finite Rings and Their Associated Graphs;Angel,1993
3. Special functions on finite upper half planes;Angel,1992
4. Spherical functions, and transforms on finite upper half planes: Eigenvalues of the combinatorial Laplaican, uncertainty, traces;Angel,1993
5. Graph spectra for finite upper half planes over rings;Angel;Linear Algebra Appl.,1995