@article{GDZPPN001251155, title = {The bicommutator of the injective hull of a nonsingular semigroup.}, journal = {Semigroup forum}, volume = {12}, year = {1976}, pages = {71-77}, zbl = {0322.20033}, url = {http://dml.mathdoc.fr/item/GDZPPN001251155} }
Lopez, A. M.; Luedeman, J.K. The bicommutator of the injective hull of a nonsingular semigroup.. Semigroup forum, Tome 12 (1976) pp. 71-77. http://gdmltest.u-ga.fr/item/GDZPPN001251155/