@article{10_4153_CJM_1993_032_9,
     author = {McLaughlin, D. and Poliquin, R. and Vanderwerff, J. and Zizler, V.},
     title = {Second-Order {G\^ateaux} {Differentiable} {Bump} {Functions} and {Approximations} in {Banach} {Spaces}},
     journal = {Canadian journal of mathematics},
     pages = {612--625},
     year = {1993},
     volume = {45},
     number = {3},
     doi = {10.4153/CJM-1993-032-9},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1993-032-9/}
}