@article{10_4153_CJM_1973_054_7,
     author = {Jonker, L. B. and Norman, R. D.},
     title = {Locally {Convex} {Hypersurfaces}},
     journal = {Canadian journal of mathematics},
     pages = {531--538},
     year = {1973},
     volume = {25},
     number = {3},
     doi = {10.4153/CJM-1973-054-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1973-054-7/}
}