@article{10_4153_CMB_1972_037_2,
     author = {Helfenstein, H. G.},
     title = {A {Flat} {Nonmetrizable} {Connexion}},
     journal = {Canadian mathematical bulletin},
     pages = {205--206},
     year = {1972},
     volume = {15},
     number = {2},
     doi = {10.4153/CMB-1972-037-2},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1972-037-2/}
}