@article{PismaZhETF.16.279,
    title = {Dynamic Negative Conductivity Due to Nonlinearity of the Current Voltage Characteristic and to the Finite Electric-conductivity Relaxation Time},
    author = {Zhdanov, M. G. and Zil'berman, P. E. and Kagan, M. S. and Kalashnikov, S. G.},
    journal = {Письма в ЖЭТФ},
    volume = {16},
    issue = {5},
    pages = {279},
    year = {1972},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26823.shtml},
}