@article{GDZPPN001260626, title = {The minimal ideal of compact subsemigroups of \ss\ S.}, journal = {Semigroup forum}, volume = {40}, year = {1990}, pages = {201-214}, zbl = {0842.22001}, url = {http://dml.mathdoc.fr/item/GDZPPN001260626} }
Davenport, D. The minimal ideal of compact subsemigroups of ß S.. Semigroup forum, Tome 40 (1990) pp. 201-214. http://gdmltest.u-ga.fr/item/GDZPPN001260626/