@article{10_4064_cm_25_2_259_264,
     author = {J. E. Valentine and S. G. Wayment},
     title = {Metric characterizations of hyperbolic and {Euclidean} spaces},
     journal = {Colloquium Mathematicum},
     pages = {259--264},
     publisher = {mathdoc},
     volume = {25},
     number = {2},
     year = {1972},
     doi = {10.4064/cm-25-2-259-264},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-25-2-259-264/}
}