%0 Journal Article %A Sebbar, Abdellah %T Modular Subgroups, Forms, Curves and Surfaces %J Canadian mathematical bulletin %D 2002 %P 294-308 %V 45 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-2002-033-1/ %R 10.4153/CMB-2002-033-1 %F 10_4153_CMB_2002_033_1