@article{PismaZhETF.30.97,
    title = {Instability of unrestricted cumulation},
    author = {Zebakhin, E. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {30},
    issue = {2},
    pages = {97},
    year = {1979},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_20591.shtml},
}