@article{TM_1976_140_a13,
     author = {V. R. Portnov},
     title = {S. {L.~Sobolev} projection operators for seminorms with infinite-dimensional kernels},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     pages = {252--263},
     year = {1976},
     volume = {140},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TM_1976_140_a13/}
}