@article{CMJ_2004__54_4_a8,
     author = {Zhang, Xiao-Dong},
     title = {A note on ultrametric matrices},
     journal = {Czechoslovak Mathematical Journal},
     pages = {929--940},
     publisher = {mathdoc},
     volume = {54},
     number = {4},
     year = {2004},
     mrnumber = {2100005},
     zbl = {1080.15500},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_2004__54_4_a8/}
}