@article{IM_1990__101_2_143823,
     author = {Yoshihiro Koya},
     title = {A generalization of class formation by using hypercohomology.},
     journal = {Inventiones mathematicae},
     pages = {705--716},
     publisher = {mathdoc},
     volume = {101},
     number = {2},
     year = {1990},
     zbl = {0751.11055},
     url = {http://geodesic.mathdoc.fr/item/IM_1990__101_2_143823/}
}