@article{702172,
title = {Integral manifolds and nonlinear oscillations},
booktitle = {Differential Equations and Their Applications},
series = {GDML\_Books},
publisher = {Publishing House of the Czechoslovak Academy of Sciences},
address = {Prague},
year = {1963},
pages = {39-54},
mrnumber = {MR0173822},
zbl = {0132.07102},
url = {http://dml.mathdoc.fr/item/702172}
}
Hale, Jack K. Integral manifolds and nonlinear oscillations, dans Differential Equations and Their Applications, GDML_Books, (1963), pp. 39-54. http://gdmltest.u-ga.fr/item/702172/