@article{IM_1986__85_143360,
     author = {M.S. Raghunathan},
     title = {On the congruence subgroup problem, {II.}},
     journal = {Inventiones mathematicae},
     pages = {73--118},
     year = {1986},
     volume = {85},
     zbl = {0603.20044},
     url = {http://geodesic.mathdoc.fr/item/IM_1986__85_143360/}
}