@article{MZ_1992__211_3_174455,
     author = {Kuniaki Horie},
     title = {On a ratio between relative class numbers.},
     journal = {Mathematische Zeitschrift},
     pages = {505--522},
     publisher = {mathdoc},
     volume = {211},
     number = {3},
     year = {1992},
     zbl = {0761.11039},
     url = {http://geodesic.mathdoc.fr/item/MZ_1992__211_3_174455/}
}