@article{AIF_1992__42_4_805_0,
     author = {Artino, R. A. and Barros-Neto, J.},
     title = {Matrix triangulation of hypoelliptic boundary value problems},
     journal = {Annales de l'Institut Fourier},
     pages = {805--824},
     publisher = {Institut Fourier},
     address = {Grenoble},
     volume = {42},
     number = {4},
     year = {1992},
     doi = {10.5802/aif.1310},
     mrnumber = {93k:35287},
     zbl = {0758.35098},
     language = {en},
     url = {http://archive.numdam.org/articles/10.5802/aif.1310/}
}