@article{CMJ_1999__49_4_a12,
     author = {Fejzi\'c, Hajrudin and Rinne, Dan and Weil, Clifford},
     title = {Extending $n$ times differentiable functions of several variables},
     journal = {Czechoslovak Mathematical Journal},
     pages = {825--830},
     publisher = {mathdoc},
     volume = {49},
     number = {4},
     year = {1999},
     mrnumber = {1746707},
     zbl = {1005.26007},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMJ_1999__49_4_a12/}
}