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@article{DAN_1983_271_5_a12, author = {S. A. Shcherbakov}, title = {The degree of smoothness of horospheres, radial fields, and}, journal = {Doklady Akademii Nauk}, pages = {1078--1082}, publisher = {mathdoc}, volume = {271}, number = {5}, year = {1983}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1983_271_5_a12/} }
S. A. Shcherbakov. The degree of smoothness of horospheres, radial fields, and. Doklady Akademii Nauk, Tome 271 (1983) no. 5, pp. 1078-1082. http://geodesic.mathdoc.fr/item/DAN_1983_271_5_a12/