@article{PIM_2011_N_S_90_104_a6,
     author = {Charles Delorme},
     title = {Spectra and {Graph} {Comparison}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {99 },
     publisher = {mathdoc},
     volume = {_N_S_90},
     number = {104},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_2011_N_S_90_104_a6/}
}