@article{PismaZhETF.33.633,
    title = {The use of thermal ballistic pulses to excite EPR signals in the upper Stark states of the impurity $Er^{3+}$ ion in an $LiYF_4$ crystal},
    author = {Al'tshuler, S. A. and Antipin, A. A. and Rakhmatullin, R. M. and Rozentsvaig, Yu. K. and Fedii, A. A. and Shlenkin, V. I.},
    journal = {Письма в ЖЭТФ},
    volume = {33},
    issue = {12},
    pages = {633},
    year = {1981},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23100.shtml},
}