@article{GDZPPN00228328X,
title = {Separation der Variablen in HILBERTschen R\"aumen.},
journal = {Mathematische Annalen},
volume = {125},
year = {1952},
pages = {401-434},
zbl = {0050.11801},
url = {http://dml.mathdoc.fr/item/GDZPPN00228328X}
}
Cordes, H.O. Separation der Variablen in HILBERTschen Räumen.. Mathematische Annalen, Tome 125 (1952) pp. 401-434. http://gdmltest.u-ga.fr/item/GDZPPN00228328X/