@inproceedings{karl-joachim2000a,
title={A short proof of a theorem of Bertilsson by direct use of Löwner’s method},
author={Karl-Joachim Wirths},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203603131784779},
booktitle={Arkiv for Matematik},
volume={39},
number={2},
pages={395-398},
year={2000},
}
Karl-Joachim Wirths. A short proof of a theorem of Bertilsson by direct use of Löwner’s method. 2000. Vol. 39. In Arkiv for Matematik. pp.395-398. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203603131784779.