@article{SEMR_2017_14_a60, author = {V. N. Stepanov}, title = {A characteristic property of the ball}, journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a}, pages = {614--619}, publisher = {mathdoc}, volume = {14}, year = {2017}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/SEMR_2017_14_a60/} }