@article{MAN_1981__257_163558,
     author = {Bernd Droste},
     title = {Holomorphic {Approximation} of {Ultradifferentiable} {Functions.}},
     journal = {Mathematische Annalen},
     pages = {293--316},
     publisher = {mathdoc},
     volume = {257},
     year = {1981},
     zbl = {0463.32007},
     url = {http://geodesic.mathdoc.fr/item/MAN_1981__257_163558/}
}