@article{IVM_1987_10_a4,
     author = {G. A. Ser\"egin},
     title = {On the differentiability of local extremals of variational problems of the mechanics of rigidly viscoplastic media},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {23--30},
     publisher = {mathdoc},
     number = {10},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1987_10_a4/}
}