@article{MM2_1994__83_3-4_155951,
     author = {Michael Langenbruch},
     title = {Extension of ultradifferentiable functions.},
     journal = {Manuscripta mathematica},
     pages = {123--144},
     publisher = {mathdoc},
     volume = {83},
     number = {3-4},
     year = {1994},
     zbl = {0836.46027},
     url = {http://geodesic.mathdoc.fr/item/MM2_1994__83_3-4_155951/}
}