@article{PismaZhETF.17.419,
    title = {Biexcitans   in  $HgI_2$  Crystals},
    author = {Akopyan, I. Kh. and Novikov, B. V. and Pimonenko, M. M. and Razbirin, B. S.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {17},
    issue = {8},
    pages = {419},
    year = {1973},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_23583.shtml},
}