@inproceedings{juha1994taken's,
title={Taken's problem for systems of first order differential equations},
author={Juha Pohjanpelto},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203546555659649},
booktitle={Arkiv for Matematik},
volume={33},
number={2},
pages={343-356},
year={1994},
}
Juha Pohjanpelto. Taken's problem for systems of first order differential equations. 1994. Vol. 33. In Arkiv for Matematik. pp.343-356. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203546555659649.