@article{1077379131, author = {Isaacs, I. M.}, title = {Groups with many equal classes}, journal = {Duke Math. J.}, volume = {37}, number = {1}, year = {1970}, pages = { 501-506}, language = {en}, url = {http://dml.mathdoc.fr/item/1077379131} }
Isaacs, I. M. Groups with many equal classes. Duke Math. J., Tome 37 (1970) no. 1, pp. 501-506. http://gdmltest.u-ga.fr/item/1077379131/