@article{ZNSL_1988_167_a10,
     author = {N. M. Gulevich},
     title = {On the radius of a compact set in {Hilbert} space},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {157--158},
     publisher = {mathdoc},
     volume = {167},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1988_167_a10/}
}