@article{10_4064_cm_38_1_53_64,
     author = {J. P{\l}onka},
     title = {On discrete subspaces of a {Hilbert} space},
     journal = {Colloquium Mathematicum},
     pages = {53--54},
     publisher = {mathdoc},
     volume = {38},
     number = {1},
     year = {1977},
     doi = {10.4064/cm-38-1-53-64},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-38-1-53-64/}
}