@article{CLTM_1976_1976_1_a6,
     author = {Mart{\'\i}nez Verduch, J. R.},
     title = {Fischer classes in finite groups.},
     journal = {Collectanea mathematica},
     pages = {109-117},
     year = {1976},
     volume = {27},
     number = {2},
     zbl = {0354.20021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CLTM_1976_1976_1_a6/}
}