@article{PismaZhETF.5.235,
    title = {Negative Conductivity Produced under the Influence of Hypersonic Flux},
    author = {Epshtein, E. M.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {5},
    issue = {7},
    pages = {235},
    year = {1967},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25153.shtml},
}