%0 Journal Article %A Kuniaki Horie %A Mitsuko Horie %T CM-fields and exponents of their ideal class groups %J Acta Arithmetica %D 1990 %P 157-170 %V 55 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/aa-55-2-157-170/ %R 10.4064/aa-55-2-157-170 %G en %F 10_4064_aa_55_2_157_170