@article{ZNSL_1987_162_a2,
     author = {F. Gryunvald and Yu. Elstrodt and E. Mennike},
     title = {Some remarks on discrete subgroups of  $SL_2(\mathbb{C})$},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {77--106},
     publisher = {mathdoc},
     volume = {162},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1987_162_a2/}
}