@article{TM_1951_38_a1,
     author = {A. D. Aleksandrov},
     title = {A theorem on triangles in a metric space and some of its applications},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {5--23},
     publisher = {mathdoc},
     volume = {38},
     year = {1951},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1951_38_a1/}
}