@article{PismaZhETF.46.186,
    title = {Measurement of the energy gap in the compound $YBa_Cu_3O_{9-\delta}$ on the basis of the IR absorption spectrum},
    author = {Gershenzon, E. M. and Gol'tsman, G. N. and Karasik, B. S. and Semenov, A. D.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {46},
    issue = {5},
    pages = {186},
    year = {1987},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_18550.shtml},
}