@article{DAN_1968_183_1_a3,
     author = {Yu. G. Borisovich and Yu. I. Sapronov},
     title = {On the topological theory of densifying operators},
     journal = {Doklady Akademii Nauk},
     pages = {18--20},
     publisher = {mathdoc},
     volume = {183},
     number = {1},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_183_1_a3/}
}