@article{IVM_2019_1_a0,
     author = {P. D. Andreev and V. V. Starostina},
     title = {Normed planes in tangent cone to chord space of nonpositive curvature},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {3--17},
     publisher = {mathdoc},
     number = {1},
     year = {2019},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2019_1_a0/}
}