@article{PismaZhETF.9.639,
    title = {Nonlinear Effects in a Superconductor in an Alternating Field},
    author = {Fedorov, M. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {9},
    issue = {11},
    pages = {639},
    year = {1969},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25418.shtml},
}