%0 Journal Article %T Exponential Sums on Reduced Residue Systems %J Canadian mathematical bulletin %D 1998 %P 187-195 %V 41 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4153/CMB-1998-028-5/ %R 10.4153/CMB-1998-028-5 %F 10_4153_CMB_1998_028_5