@article{RM_1999_54_6_a2,
     author = {L. O. Chekhov},
     title = {A~spectral problem on graphs and $L$-functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {1197--1232},
     publisher = {mathdoc},
     volume = {54},
     number = {6},
     year = {1999},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/RM_1999_54_6_a2/}
}