@article{MMO_1972_26_a0,
     author = {A. D. Ioffe and V. L. Levin},
     title = {Subdifferentials of convex functions},
     journal = {Trudy Moskovskogo matemati\v{c}eskogo ob\^{s}estva},
     pages = {3--73},
     publisher = {mathdoc},
     volume = {26},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MMO_1972_26_a0/}
}