@article{PismaZhETF.8.489,
    title = {Quantum Spin Waves},
    author = {Zyryanov, P. S. and Okulov, V. I and Silin, V. P.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {8},
    issue = {9},
    pages = {489},
    year = {1968},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26034.shtml},
}