@book{PPN376499427, title = {Pr\"azisions - und Approximationsmathematik Bd. 3}, series = {GDML\_Books}, year = {1968}, language = {ger}, url = {http://dml.mathdoc.fr/item/PPN376499427} }
(éd.). Präzisions - und Approximationsmathematik Bd. 3. GDML_Books (1968), http://gdmltest.u-ga.fr/item/PPN376499427/