On a functorial property of power residue symbols. Erratum : Solution of the congruence subgroup problem for $S{L}_{n}\left(n\ge 3\right)$ and $S{p}_{2n}\left(n\ge 2\right)$
Publications Mathématiques de l'IHÉS, Tome 44 (1974) , p. 241-244
URL stable : http://www.numdam.org/item?id=PMIHES_1974__44__241_0