@article{AUCMP_2001_42_2_a1,
     author = {Cicho\'n, Jacek},
     title = {On dense subsets of rational numbers},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {5--10},
     year = {2001},
     volume = {42},
     number = {2},
     mrnumber = {1900385},
     zbl = {1001.03045},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_2001_42_2_a1/}
}