@article{DAN_1979_249_1_a7,
     author = {Yu. P. Krivenkov},
     title = {Optimality conditions for a quasilinear problem with partial differential equations in the presence of phase constraints},
     journal = {Doklady Akademii Nauk},
     pages = {37--41},
     publisher = {mathdoc},
     volume = {249},
     number = {1},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_249_1_a7/}
}