@article{JTNB_2009__21_3_721_0,
     author = {Petridis, Yiannis N. and Risager, Morten S.},
     title = {Hyperbolic lattice-point counting and modular symbols},
     journal = {Journal de th\'eorie des nombres de Bordeaux},
     pages = {721--734},
     publisher = {Universit\'e Bordeaux 1},
     volume = {21},
     number = {3},
     year = {2009},
     doi = {10.5802/jtnb.698},
     zbl = {1214.11065},
     mrnumber = {2605543},
     language = {en},
     url = {http://www.numdam.org/articles/10.5802/jtnb.698/}
}