@article{GDZPPN001259059, title = {Hausdorff topologies on the a-bicyclic semigroup.}, journal = {Semigroup forum}, volume = {36}, year = {1987}, pages = {189-210}, zbl = {0626.22002}, url = {http://dml.mathdoc.fr/item/GDZPPN001259059} }
Hogan, J.W. Hausdorff topologies on the a-bicyclic semigroup.. Semigroup forum, Tome 36 (1987) pp. 189-210. http://gdmltest.u-ga.fr/item/GDZPPN001259059/