@article{PismaZhETF.63.192,
    title = {Spin gap for multicham lattice and linearized near Fermi points quantum spin model},
    author = {Zvyagiri, A. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {63},
    issue = {3},
    pages = {192},
    year = {1996},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_14552.shtml},
}