@article{MAT_1972_16_4_a1,
     author = {Ya. Ihara},
     title = {On congruence monodromy {problems.~II}},
     journal = {Matematika},
     pages = {50--71},
     publisher = {mathdoc},
     volume = {16},
     number = {4},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1972_16_4_a1/}
}