@article{PismaZhETF.27.84,
    title = {Determination of the energy gaps in metals by an optical method},
    author = {Mash, E. D. and Motulevich, G. P. and Shubin, A. A.},
    journal = {Письма в ЖЭТФ},
    volume = {27},
    issue = {2},
    pages = {84},
    year = {1978},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23643.shtml},
}