@article{AA_2014_26_2_a0,
     author = {P. D. Andreev},
     title = {The proof of {Busemann} conjecture for $G$-spaces with non-positive curvature},
     journal = {Algebra i analiz},
     pages = {1--20},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {2014},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2014_26_2_a0/}
}