@article{PismaZhETF.21.3,
    title = {Contribution to the theory of the spectrum of a Bose system with condensate at small momenta},
    author = {Nepomnyashchii, A. A. and Nepomnyashchii, Yu. A.},
    journal = {Письма в ЖЭТФ},
    volume = {21},
    issue = {1},
    pages = {3},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22243.shtml},
}