@article{GDZPPN001264141, title = {Applications of epigroups to graded ring theory.}, journal = {Semigroup forum}, volume = {51}, year = {1995}, pages = {327-350}, zbl = {0824.16031}, url = {http://dml.mathdoc.fr/item/GDZPPN001264141} }
Kelarev, A.V. Applications of epigroups to graded ring theory.. Semigroup forum, Tome 51 (1995) pp. 327-350. http://gdmltest.u-ga.fr/item/GDZPPN001264141/