@article{NSJOM_2010_40_2a_1,
     author = {M.K. Bose, and Ajoy Mukharjee},
     title = {On countable families
 of topologies on a set},
     journal = {Novi Sad Journal of Mathematics},
     pages = {7-16},
     year = {2010},
     volume = {40},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2010_40_2a_1/}
}