@article{PismaZhETF.62.427,
    title = {Microscopic instanton dynamics in molecules and crystals. Tunneling in $NH_3$},
    author = {Katsnel'son, M. I. and Antropov, V. P. and Van Schilfgaarde, M. and Harman, B. N.},
    journal = {Письма в ЖЭТФ},
    volume = {62},
    issue = {5},
    pages = {427},
    year = {1995},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_18394.shtml},
}