@article{PismaZhETF.57.277,
    title = {Stratification of a coherent state of excitons sustained by optical pumping},
    author = {Balkarei, Yu. I. and Kogan, A. S.},
    journal = {πΙΣΨΝΑ Χ φότζ},
    volume = {57},
    issue = {5},
    pages = {277},
    year = {1993},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_17777.shtml},
}