@article{GDZPPN001187112,
title = {Two-sided approximation to periodic solutions of ordinary differential equations.},
journal = {Numerische Mathematik},
volume = {66},
year = {1993},
pages = {399-410},
zbl = {0799.65077},
url = {http://dml.mathdoc.fr/item/GDZPPN001187112}
}
Zhang, Liqing. Two-sided approximation to periodic solutions of ordinary differential equations.. Numerische Mathematik, Tome 66 (1993) pp. 399-410. http://gdmltest.u-ga.fr/item/GDZPPN001187112/