@article{AIF_1989__39_3_611_0, author = {Broglia, F. and Tognoli, A.}, title = {Approximation of $C^\infty $-functions without changing their zero-set}, journal = {Annales de l'Institut Fourier}, pages = {611--632}, publisher = {Institut Fourier}, address = {Grenoble}, volume = {39}, number = {3}, year = {1989}, doi = {10.5802/aif.1178}, zbl = {0673.14017}, mrnumber = {90k:32023}, language = {en}, url = {https://aif.centre-mersenne.org/articles/10.5802/aif.1178/} }