@article{1256053747, author = {Snapper, Ernst}, title = {Normal subsets of finite group}, journal = {Illinois J. Math.}, volume = {13}, number = {4}, year = {1969}, pages = { 155-164}, language = {en}, url = {http://dml.mathdoc.fr/item/1256053747} }
Snapper, Ernst. Normal subsets of finite group. Illinois J. Math., Tome 13 (1969) no. 4, pp. 155-164. http://gdmltest.u-ga.fr/item/1256053747/