@article{PismaZhETF.5.3,
    title = {Echo Pulses in Yttrium},
    author = {Lisovskii, F. V. and Monosov, Ya. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {5},
    issue = {1},
    pages = {3},
    year = {1967},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_25079.shtml},
}