%0 Journal Article %A Artino, R. A. %A Barros-Neto, J. %T Matrix triangulation of hypoelliptic boundary value problems %J Annales de l'Institut Fourier %D 1992 %P 805-824 %V 42 %N 4 %I Institut Fourier %C Grenoble %U http://www.numdam.org/articles/10.5802/aif.1310/ %R 10.5802/aif.1310 %G en %F AIF_1992__42_4_805_0