@article{KUIPM_1988_15_15_a0,
     author = {Z. R. Gabidullina},
     title = {Differentiability of a convex function},
     journal = {Issledovaniya po Prikladnoi Matematike i Informatike},
     pages = {3--5},
     year = {1988},
     volume = {15},
     number = {15},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUIPM_1988_15_15_a0/}
}