@article{PismaZhETF.12.429,
    title = {Threshold Phenomena in a Parametrically Excited Spin System of Ferrites},
    author = {Petrakovskii, G. A. and Berzhanskii, V. N.},
    journal = {Письма в ЖЭТФ},
    volume = {12},
    issue = {9},
    pages = {429},
    year = {1970},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26348.shtml},
}