@article{MZ_1977__157_172591,
     author = {Dietrich Bartels},
     title = {Subnormality and {Invariant} {Relations} on {Conjugacy} {Classes} in {Finite} {Groups.}},
     journal = {Mathematische Zeitschrift},
     pages = {13--18},
     publisher = {mathdoc},
     volume = {157},
     year = {1977},
     zbl = {0348.20019},
     url = {http://geodesic.mathdoc.fr/item/MZ_1977__157_172591/}
}