@article{PismaZhETF.17.197,
    title = {Spatially  Inhomogeneous Filters for  the Ultrasoft  X-ray Region},
    author = {Peskov, V. D. and Sakharov, Ya. A. and Tishchenko, E. A.},
    journal = {Письма в ЖЭТФ},
    volume = {17},
    issue = {4},
    pages = {197},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23516.shtml},
}