@misc{Ismailov_Zameddin_I._On_2003,
 author={Ismailov, Zameddin I.},
 volume={51},
 editor={Polska Akademia Nauk.},
 number={2},
 copyright={Rights Reserved - Restricted Access},
 address={Warsaw},
 howpublished={online},
 year={2003},
 publisher={Polska Akademia Nauk. Centrum Upowszechniania Nauki.},
 language={eng},
 type={Text},
 title={On the normality of first-order differential operators},
}