@article{PismaZhETF.7.32,
    title = {Singularities of the Phonon Spectrum of Crystals with Extended Defects},
    author = {Iosilevskii, Ya. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {7},
    issue = {1},
    pages = {32},
    year = {1968},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25567.shtml},
}