@article{TM_1972_117_a11,
     author = {P. I. Lizorkin},
     title = {Operators connected with fractional differentiation, and classes of differentiable functions},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {212--243},
     publisher = {mathdoc},
     volume = {117},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1972_117_a11/}
}