@article{GDZPPN002301946,
title = {Approximationstheorie f\"ur metrische lineare R\"aume.},
journal = {Mathematische Annalen},
volume = {189},
year = {1970},
pages = {30-48},
zbl = {0175.42001},
url = {http://dml.mathdoc.fr/item/GDZPPN002301946}
}
PANTELIDIS, G. Approximationstheorie für metrische lineare Räume.. Mathematische Annalen, Tome 189 (1970) pp. 30-48. http://gdmltest.u-ga.fr/item/GDZPPN002301946/