@article{PismaZhETF.52.940,
    title = {Cross-relaxation emptying of the ground state of rare-earth ions in crystals},
    author = {Noginov, M. A. and Prokhorov, A. M. and Sarkisyan, G. K. and Smirnov, V. A. and Shcherbakov, I. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {52},
    issue = {6},
    pages = {940},
    year = {1990},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_17502.shtml},
}