@article{PismaZhETF.60.845,
    title = {Non-ohmic hopping conductivity in the exponential band tail},
    author = {Gurvich, Yn. A. and Melnikov, A. P. and Shestakov, L. N. and Gersheiizon, E. M.},
    journal = {Письма в ЖЭТФ},
    volume = {60},
    issue = {12},
    pages = {845},
    year = {1994},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_5563.shtml},
}