@article{INTF_1986_9_a2,
     author = {E. A. Poletskii and B. V. Shabat},
     title = {Invariant metrics},
     journal = {Itogi Nauki i Tekhniki. Seriya Sovremennye Problemy Matematiki. Fundamental'nye Napravleniya},
     pages = {73--125},
     year = {1986},
     volume = {9},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/INTF_1986_9_a2/}
}