@article{PismaZhETF.18.80,
    title = {Gas laser using ionized europium},
    author = {Bokhan, P. A. and Klimkin, V. M. and Prokop'ev, V. E.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {18},
    issue = {2},
    pages = {80},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23886.shtml},
}