@article{AUCMP_2009_50_2_a4,
     author = {Koc, Martin},
     title = {On relations among metric derived numbers},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {39--47},
     year = {2009},
     volume = {50},
     number = {2},
     mrnumber = {2567174},
     zbl = {1183.26003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_2009_50_2_a4/}
}