@article{PismaZhETF.26.377,
    title = {Optical observation of multiphoton NMR of absorption in semiconducting crystals},
    author = {Berkovits, V. L. and Safarov, V. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {26},
    issue = {5},
    pages = {377},
    year = {1977},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_20903.shtml},
}