TY - JOUR AU - I. M. Petrushko TI - Boundary value problems for equations of mixed type JO - Informatics and Automation PY - 1968 SP - 181 EP - 200 VL - 103 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TRSPY_1968_103_a11/ LA - ru ID - TRSPY_1968_103_a11 ER -