@misc{RM_1986_41_4_a12,
     title = {Joint sessions of the {Petrovskii} {Seminar} on differential equations and mathematical problems of physics and of the {Moscow} {Mathematical} {Society} (ninth meeting, {January~20--23,~1986)}},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {41},
     number = {4},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1986_41_4_a12/}
}