Do we have any good sources(lecture notes or books) for learning about $Ihara$ Coefficient?
Is there any relation between $Ihara$ Coefficient and the eigenvalues of graphs?
Thanks for any help.
Do we have any good sources(lecture notes or books) for learning about $Ihara$ Coefficient? Is there any relation between $Ihara$ Coefficient and the eigenvalues of graphs? Thanks for any help. 


Following Igor Rivin's suggestion I found the thesis of Matthew Horton (student of Stark and Terras) pretty interesting : 'Ihara zeta functions of irregular graphs'. 


Yes, the good sources are the articles by H. Stark and A. Terras on zeta functions of graphs. 

