@article{GDZPPN001168045,
title = {On Estimating Best Approximations of Functions Defined by Differential Equations.},
journal = {Numerische Mathematik},
volume = {13},
year = {1969},
pages = {199-206},
zbl = {0174.47302},
url = {http://dml.mathdoc.fr/item/GDZPPN001168045}
}
OSBORNE, M.R.; WATSON, G.A. On Estimating Best Approximations of Functions Defined by Differential Equations.. Numerische Mathematik, Tome 13 (1969) pp. 199-206. http://gdmltest.u-ga.fr/item/GDZPPN001168045/