@misc{_Bulletin_2001,
 volume={49},
 editor={Polska Akademia Nauk.},
 copyright={Rights Reserved - Restricted Access},
 address={Warsaw},
 howpublished={online},
 year={2001},
 publisher={Państ. Wydaw. Nauk.},
 language={eng},
 type={Text},
 title={Bulletin of the Polish Academy of Sciences. Mathematics.},
}