@article{PismaZhETF.21.438,
    title = {Anisotropy of resonant absorption of high-frequency 0.87 X $10^{12}$ Hz phonons in the excited state of $Cr^{3$ +} ions in ruby},
    author = {Kaplyanskii, A. A. and Basun, S. A. and Rachin, V. A. and Titov, R. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {21},
    issue = {7},
    pages = {438},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22452.shtml},
}