@article{JRAM_1976__285_151755,
     author = {Robert W. van der Waall},
     title = {On minimal subgroups which are normal.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {77--78},
     publisher = {mathdoc},
     volume = {285},
     year = {1976},
     zbl = {0326.20020},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1976__285_151755/}
}