@article{PismaZhETF.19.176,
    title = {Diffraction limit of focusing of ultrashort light pulses by a zone plate},
    author = {Lugovoi, V. N.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {19},
    issue = {3},
    pages = {176},
    year = {1974},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_26976.shtml},
}