@article{PismaZhETF.20.734,
    title = {Nonlinear interaction of diffracted light beams in a medium with quadratic nonlinearity: mutual focusing of beams and limitation on the efficiency of optical frequency converters},
    author = {Karamzin, Yu. N. and Sukhorukov, A. P.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {20},
    issue = {11},
    pages = {734},
    year = {1974},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_27398.shtml},
}