@article{MZ_1957__68_169699,
     author = {Chih-Han Sah},
     title = {On a generalization of finite nilpotent groups.},
     journal = {Mathematische Zeitschrift},
     pages = {189--204},
     publisher = {mathdoc},
     volume = {68},
     year = {1957},
     zbl = {0079.25501},
     url = {http://geodesic.mathdoc.fr/item/MZ_1957__68_169699/}
}