@article{SF_1989__38_2_134966,
     author = {John Dauns},
     title = {Centers of semigroup rings and conjugacy classes.},
     journal = {Semigroup forum},
     pages = {355--364},
     publisher = {mathdoc},
     volume = {38},
     number = {2},
     year = {1989},
     zbl = {0655.16001},
     url = {http://geodesic.mathdoc.fr/item/SF_1989__38_2_134966/}
}