@misc{_Bulletin_1999,
 volume={47},
 number={1-4},
 editor={Polska Akademia Nauk.},
 copyright={Rights Reserved - Restricted Access},
 address={Warsaw},
 howpublished={online},
 year={1999},
 publisher={Polska Akademia Nauk. Centrum Upowszechniania Nauki.},
 language={eng},
 title={Bulletin of the Polish Academy of Sciences. Mathematics.},
 type={Text},
}