@article{1029000515,
author = {Holzsager, R. A. and Wu, H.},
title = {A characterization of two-dimensional Riemannian manifolds of constant curvature.},
journal = {Michigan Math. J.},
volume = {17},
number = {1},
year = {1970},
pages = { 297-299},
language = {en},
url = {http://dml.mathdoc.fr/item/1029000515}
}
Holzsager, R. A.; Wu, H. A characterization of two-dimensional Riemannian manifolds of constant curvature.. Michigan Math. J., Tome 17 (1970) no. 1, pp. 297-299. http://gdmltest.u-ga.fr/item/1029000515/