@article{GDZPPN001259776,
title = {Centers of semigroup rings and conjugacy classes.},
journal = {Semigroup forum},
volume = {38},
year = {1989},
pages = {355-364},
zbl = {0655.16001},
url = {http://dml.mathdoc.fr/item/GDZPPN001259776}
}
Dauns, John. Centers of semigroup rings and conjugacy classes.. Semigroup forum, Tome 38 (1989) pp. 355-364. http://gdmltest.u-ga.fr/item/GDZPPN001259776/