@article{PMIHES_1967__33__59_0,
     author = {Hyman Bass and John Milnor and Jean-Pierre Serre},
     title = {Solution of the congruence subgroup problem for $SL_n (n \ge 3)$ and $Sp_{2n} (n \ge 2)$},
     journal = {Publications Math\'ematiques de l'IH\'ES},
     pages = {59--137},
     year = {1967},
     publisher = {Institut des Hautes \'Etudes Scientifiques},
     volume = {33},
     doi = {10.1007/BF02684586},
     mrnumber = {39 #5574},
     zbl = {0174.05203},
     language = {en},
     url = {https://pmihes.centre-mersenne.org/articles/10.1007/BF02684586/}
}