@article{PismaZhETF.33.410,
    title = {A narrow phonon neck in the luminescence of $CaF_2-Eu^{+}$ crystals and the anharmonic lifetime of terahertz acoustic phonons},
    author = {Akimov, A. V. and Kaplyanskii, A. A. and Syrkin, A. L.},
    journal = {Письма в ЖЭТФ},
    volume = {33},
    issue = {8},
    pages = {410},
    year = {1981},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23042.shtml},
}