@article{MVK_2011_2_a3,
     author = {B. A. Pogorelov and M. A. Pudovkina},
     title = {Natural metrics and their properties. {P.~1.} {Submetrics} and overmetrics},
     journal = {Matemati\v{c}eskie voprosy kriptografii},
     pages = {49--74},
     publisher = {mathdoc},
     volume = {2},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MVK_2011_2_a3/}
}