@article{2528, author = {Hill, Paul}, title = {Concerning anti-closed subsets in semigroups}, journal = {Portugaliae mathematica}, volume = {26}, year = {1967}, pages = {193-200}, zbl = {0183.02203}, mrnumber = {0248264}, language = {en}, url = {http://dml.mathdoc.fr/item/2528} }
Hill, Paul. Concerning anti-closed subsets in semigroups. Portugaliae mathematica, Tome 26 (1967) pp. 193-200. http://gdmltest.u-ga.fr/item/2528/