@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/