@article{PismaZhETF.28.673,
    title = {Experimental observation of diffraction focusing of a spherical x-ray wave},
    author = {Koz'mik, V. D. and Mikhailyuk, I. P.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {28},
    issue = {11},
    pages = {673},
    year = {1978},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24254.shtml},
}