@article{MZM_1975_17_2_a6,
     author = {G. I. Gusev},
     title = {Poincar\'e series},
     journal = {Matemati\v{c}eskie zametki},
     pages = {245--254},
     year = {1975},
     volume = {17},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1975_17_2_a6/}
}