@article{1178244920, author = {Nasu, Yasuo}, title = {On asymptotes in a metric space with non-positive curvature}, journal = {Tohoku Math. J. (2)}, volume = {9}, number = {3}, year = {1957}, pages = { 68-95}, language = {en}, url = {http://dml.mathdoc.fr/item/1178244920} }
Nasu, Yasuo. On asymptotes in a metric space with non-positive curvature. Tohoku Math. J. (2), Tome 9 (1957) no. 3, pp. 68-95. http://gdmltest.u-ga.fr/item/1178244920/