@article{PismaZhETF.13.558,
    title = {Polarization Echo in the Ferroelectric Single Crystal $KH_2PO_4$},
    author = {Kopvillem, U. Kh. and Smolyakov, B. P. and Sharipov, R. Z.},
    journal = {Письма в ЖЭТФ},
    volume = {13},
    issue = {10},
    pages = {558},
    year = {1971},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24338.shtml},
}