@article{DAN_1988_300_2_a8,
     author = {S. V. Yushmanov},
     title = {Metric properties of chordal and {Ptolemaic} graphs},
     journal = {Doklady Akademii Nauk},
     pages = {296--299},
     publisher = {mathdoc},
     volume = {300},
     number = {2},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1988_300_2_a8/}
}