@article{02012560, title = {On some center-like subsets of groups.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {2003}, year = {2003}, pages = {2583-2586}, doi = {10.1155/S016117120330328X}, zbl = {1036.20036}, language = {en}, url = {http://dml.mathdoc.fr/item/02012560} }
Klein, Abraham A.; Bell, Howard E. On some center-like subsets of groups.. International Journal of Mathematics and Mathematical Sciences, Tome 2003 (2003) pp. 2583-2586. doi : 10.1155/S016117120330328X. http://gdmltest.u-ga.fr/item/02012560/