@article{TM_2011_275_a18,
     author = {M. I. Monastyrsky},
     title = {Hecke graphs, {Ramanujan} graphs and generalized duality transformations for lattice spin systems},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {295--300},
     publisher = {mathdoc},
     volume = {275},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TM_2011_275_a18/}
}