@article{PismaZhETF.28.6,
    title = {Observation of the focusing of x rays diffracted by a perfect crystal},
    author = {Aristov, V. V. and Polovinkina, V. I. and Shmyt'ko, I. M. and Shulakov, E. V.},
    journal = {Письма в ЖЭТФ},
    volume = {28},
    issue = {1},
    pages = {6},
    year = {1978},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23811.shtml},
}