Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1982_31_5_a11, author = {V. S. Balaganskii}, title = {Approximative properties of sets in {Hilbert} space}, journal = {Matemati\v{c}eskie zametki}, pages = {785--800}, publisher = {mathdoc}, volume = {31}, number = {5}, year = {1982}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1982_31_5_a11/} }
V. S. Balaganskii. Approximative properties of sets in Hilbert space. Matematičeskie zametki, Tome 31 (1982) no. 5, pp. 785-800. http://geodesic.mathdoc.fr/item/MZM_1982_31_5_a11/