@article{PismaZhETF.54.201,
    title = {Spectrum of gravitational waves in a double-inflation scenario},
    author = {Zel'nikov, M. I. and Mukhanov, V. F.},
    journal = {Письма в ЖЭТФ},
    volume = {54},
    issue = {4},
    pages = {201},
    year = {1991},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_18119.shtml},
}