@article{PismaZhETF.52.1179,
    title = {Anomalies in the quantum excitation spectrum of a magnetic material with a strong quasiparticle interaction},
    author = {Val'kov, V. V. and Val'kova, T. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {52},
    issue = {11},
    pages = {1179},
    year = {1990},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_17569.shtml},
}