@article{1183510611,
author = {Busemann, Herbert},
title = {Two-dimensional geometries with elementary areas},
journal = {Bull. Amer. Math. Soc.},
volume = {53},
number = {12},
year = {1947},
pages = { 402-407},
language = {en},
url = {http://dml.mathdoc.fr/item/1183510611}
}
Busemann, Herbert. Two-dimensional geometries with elementary areas. Bull. Amer. Math. Soc., Tome 53 (1947) no. 12, pp. 402-407. http://gdmltest.u-ga.fr/item/1183510611/