@article{05068464, title = {The number of topologies on a finite set.}, journal = {Journal of Integer Sequences [electronic only]}, volume = {9}, year = {2006}, zbl = {1103.11007}, language = {en}, url = {http://dml.mathdoc.fr/item/05068464} }
Benoumhani, Moussa. The number of topologies on a finite set.. Journal of Integer Sequences [electronic only], Tome 9 (2006) . http://gdmltest.u-ga.fr/item/05068464/