@article{PismaZhETF.51.259,
    title = {Second (quantum) threshold of a laser},
    author = {Oraevskii, A. N.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {51},
    issue = {5},
    pages = {259},
    year = {1990},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_17245.shtml},
}