@article{MT_2010_13_1_a1,
     author = {V. N. Berestovskii},
     title = {On a~problem by {V.} {A.~Toponogov}},
     journal = {Matemati\v{c}eskie trudy},
     pages = {15--22},
     year = {2010},
     volume = {13},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_2010_13_1_a1/}
}