@article{IVM_2010_9_a1, author = {P. D. Andreev}, title = {A.\,D.~Alexandrov's problem for non-positively curved spaces in the sense of {Busemann}}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {10--35}, publisher = {mathdoc}, number = {9}, year = {2010}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_2010_9_a1/} }