TY - JOUR AU - Sjöstrand, Johannes TI - Propagation of singularities for operators with multiple involutive characteristics JO - Annales de l'Institut Fourier PY - 1976 DA - 1976/// SP - 141 EP - 155 VL - 26 IS - 1 PB - Institut Fourier UR - http://www.numdam.org/articles/10.5802/aif.602/ UR - https://zbmath.org/?q=an%3A0313.58021 UR - https://www.ams.org/mathscinet-getitem?mr=54 #13285 UR - https://doi.org/10.5802/aif.602 DO - 10.5802/aif.602 LA - en ID - AIF_1976__26_1_141_0 ER -