@article{PismaZhETF.97.344,
    title = {Nambu sum rule in the NJL models: from superfluidity to top quark condensation},
    author = {Volovik, G. E. and Zubkov, M. A.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {97},
    issue = {6},
    pages = {344},
    year = {2013},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_30232.shtml},
}