@article{CMJ_2005__55_1_a4,
     author = {Ding, Changming},
     title = {The omega limit sets of subsets in a metric space},
     journal = {Czechoslovak Mathematical Journal},
     pages = {87--96},
     publisher = {mathdoc},
     volume = {55},
     number = {1},
     year = {2005},
     mrnumber = {2121657},
     zbl = {1081.37001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2005__55_1_a4/}
}