@article{RSMUP_1992__87__245_0,
     author = {Kappe, Luise-Charlotte and Ying, John H.},
     title = {On exact power margin groups},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {245--265},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {87},
     year = {1992},
     mrnumber = {1183910},
     zbl = {0772.20006},
     language = {en},
     url = {http://archive.numdam.org/item/RSMUP_1992__87__245_0/}
}