@article{VSPUI_2013_3_a5,
     author = {V. F. Demyanov and M. V. Dolgopolik},
     title = {Codifferentiable functions in {Banach} spaces: methods and applications to problems of variation calculus},
     journal = {Vestnik Sankt-Peterburgskogo universiteta. Prikladna\^a matematika, informatika, processy upravleni\^a},
     pages = {48--66},
     publisher = {mathdoc},
     number = {3},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VSPUI_2013_3_a5/}
}