@article{PismaZhETF.48.565,
    title = {Toroidal excitons in crystals},
    author = {Kopaev, Yu. V. and Kornyakov, N. V.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {48},
    issue = {10},
    pages = {565},
    year = {1988},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_16795.shtml},
}