@article{PismaZhETF.106.220,
    title = {Effective Minkowski to Euclidean signature change of the magnon  BEC pseudo-Goldstone mode in polar $^3$He},
    author = {Nissinen, J. and Volovik, G. E.},
    journal = {Письма в ЖЭТФ},
    volume = {106},
    issue = {4},
    pages = {220},
    year = {2017},
    doi = {10.7868/S0370274X17160068},
    url = {http://jetpletters.ru/ps/dx/10.7868/S0370274X17160068},
    note = {[JETP Letters 106, 234 (2017)]}
}