@article{PismaZhETF.69.465,
    title = {Hamiltonian averaging and integrability  in nonlinear systems with  periodically varying dispersion},
    author = {Medvedev, S. B. and Turitsyn, S. K.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {69},
    issue = {7},
    pages = {465},
    year = {1999},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_14189.shtml},
}