@article{TM_1992_201_a12,
     author = {P. I. Lizorkin and V. S. Guliev},
     title = {Functional spaces and approximation problems on {Heisenberg} group},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {245--272},
     publisher = {mathdoc},
     volume = {201},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1992_201_a12/}
}