@article{PismaZhETF.54.437,
    title = {Laser stepped resonant photoelectric effect involving $Nd^{3+}$ dopant ions at the surface of a $ZrO_2$ crystal},
    author = {Letokhov, V. S. and Sekatskii, S. K. and Mirov, S. B.},
    journal = {Письма в ЖЭТФ},
    volume = {54},
    issue = {8},
    pages = {437},
    year = {1991},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_18923.shtml},
}