@article{DAN_1969_189_4_a13,
     author = {A. F. Shapkin},
     title = {On nondetermined methods of solving {Poisson{\textquoteright}s} equation optimal on function classes},
     journal = {Doklady Akademii Nauk},
     pages = {744--747},
     publisher = {mathdoc},
     volume = {189},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_189_4_a13/}
}