@article{DE_1990_26_6_a12,
     author = {G. A. Seregin},
     title = {Differential properties of extremals of variational problems that arise in the theory of plasticity},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1033--1044},
     publisher = {mathdoc},
     volume = {26},
     number = {6},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_6_a12/}
}