TY - JOUR AU - V. A. Koibaev TI - On a~question about generalized congruence subgroups.~I JO - Zapiski Nauchnykh Seminarov POMI PY - 2018 SP - 105 EP - 110 VL - 470 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/ZNSL_2018_470_a5/ LA - ru ID - ZNSL_2018_470_a5 ER -