@article{GDZPPN001248251, title = {Is minimal group congruence smallest?}, journal = {Semigroup forum}, volume = {4}, year = {1972}, pages = {173-176}, zbl = {0256.20080}, url = {http://dml.mathdoc.fr/item/GDZPPN001248251} }
Tamura, T.; Hamilton, H.B. Is minimal group congruence smallest?. Semigroup forum, Tome 4 (1972) pp. 173-176. http://gdmltest.u-ga.fr/item/GDZPPN001248251/