Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MAT_1958_2_2_a3, author = {L. Flatto and N. Levins{\cyro}n}, title = {Periodic solutions of singularly perturbed systems}, journal = {Matematika}, pages = {61--68}, publisher = {mathdoc}, volume = {2}, number = {2}, year = {1958}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MAT_1958_2_2_a3/} }
L. Flatto; N. Levinsоn. Periodic solutions of singularly perturbed systems. Matematika, Tome 2 (1958) no. 2, pp. 61-68. http://geodesic.mathdoc.fr/item/MAT_1958_2_2_a3/