@article{CMUC_2009_50_1_a12,
     author = {Stasyuk, I. and Tymchatyn, E. D.},
     title = {A continuous operator extending ultrametrics},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {141--151},
     year = {2009},
     volume = {50},
     number = {1},
     mrnumber = {2562811},
     zbl = {1212.54091},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2009_50_1_a12/}
}