@article{DAN_1970_194_2_a6,
     author = {V. L. Levin},
     title = {The subdifferential of a composite functional},
     journal = {Doklady Akademii Nauk},
     pages = {268--269},
     publisher = {mathdoc},
     volume = {194},
     number = {2},
     year = {1970},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1970_194_2_a6/}
}