@article{MZ_1996__222_3_174904,
     author = {Roland Matthes},
     title = {The {Eisenstein} family for the modular group along closed geodescis.},
     journal = {Mathematische Zeitschrift},
     pages = {627--654},
     publisher = {mathdoc},
     volume = {222},
     number = {3},
     year = {1996},
     zbl = {0868.11023},
     url = {http://geodesic.mathdoc.fr/item/MZ_1996__222_3_174904/}
}