%0 Journal Article %A P. I. Lizorkin %A V. S. Guliev %T Functional spaces and approximation problems on Heisenberg group %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1992 %P 245-272 %V 201 %I mathdoc %U http://geodesic.mathdoc.fr/item/TM_1992_201_a12/ %G ru %F TM_1992_201_a12