@article{PismaZhETF.14.301,
    title = {Excitation Energy Transfer between Trivalent Rare-earth Ions, Stimulated by a Radiation Field},
    author = {Bilak, V. I. and Zverev, G. M. and Karapetyan, G. O. and Onishchenko, A. M.},
    journal = {Письма в ЖЭТФ},
    volume = {14},
    issue = {5},
    pages = {301},
    year = {1971},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_24888.shtml},
}