@article{03953306, title = {Generalized multitime expansions for equations with slowly varying coefficients.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {7}, year = {1984}, pages = {151-158}, doi = {10.1155/S0161171284000156}, zbl = {0593.34054}, language = {en}, url = {http://dml.mathdoc.fr/item/03953306} }
Levine, L.E.; Obi, W.C. Generalized multitime expansions for equations with slowly varying coefficients.. International Journal of Mathematics and Mathematical Sciences, Tome 7 (1984) pp. 151-158. doi : 10.1155/S0161171284000156. http://gdmltest.u-ga.fr/item/03953306/