TY - JOUR AU - G. A. Seregin TI - Differential properties of extremals of variational problems in the mechanics of viscoplastic media JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1990 SP - 117 EP - 124 VL - 188 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1990_188_a5/ LA - ru ID - TM_1990_188_a5 ER -