@article{PismaZhETF.21.693,
    title = {Nonlinear absorption of sound in gallium in the  superconducting state},
    author = {Fil', V. D. and Denisenko, V. L and Bezuglyi, P. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {21},
    issue = {12},
    pages = {693},
    year = {1975},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_22529.shtml},
}