@article{PismaZhETF.31.631,
    title = {Production of sound waves in the early universe},
    author = {Lukash, V. N.},
    journal = {Письма в ЖЭТФ},
    volume = {31},
    issue = {11},
    pages = {631},
    year = {1980},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_20496.shtml},
}