@article{JETPL.110.335,
    title = {},
    author = {Volovik, G. E.},
    journal = {JETP Lett.},
    volume = {110},
    issue = {5},
    pages = {352},
    year = {2019},
    doi = {},
    url = {http://jetpletters.ru/ps/dx/10.1134/S0370274X19170090},
    note = {[Pisma v ZhETF 110, 335 (2019)]}
}