@article{10_4153_CMB_1974_075_4,
     author = {Whitfield, J. H. M.},
     title = {Quasi-Differentiable {Norms}},
     journal = {Canadian mathematical bulletin},
     pages = {407--408},
     year = {1974},
     volume = {17},
     number = {3},
     doi = {10.4153/CMB-1974-075-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1974-075-4/}
}