TY - JOUR AU - È. B. Vinberg TI - The smallest field of definition of a~subgroup of the~group $\mathrm{PSL}_2$ JO - Sbornik. Mathematics PY - 1995 SP - 179 EP - 190 VL - 80 IS - 1 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/SM_1995_80_1_a8/ LA - en ID - SM_1995_80_1_a8 ER -