@article{PismaZhETF.70.664,
    title = {Subattosecond ($ \leq 10^{-18} $s) time measurements using coherent x-ray transition radiation},
    author = {Gazazian, E. D. and Ispirian, K. A. and Ispirian, R. K. and Ivanian, M. I.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {70},
    issue = {10},
    pages = {664},
    year = {1999},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_14076.shtml},
}