@inproceedings{darya1999linear,
title={Linear two-phase Venttsel problems},
author={Darya E. Apushkinskaya, and Aleksandr I. Nazarov},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203601762758769},
booktitle={Arkiv for Matematik},
volume={39},
number={2},
pages={201-222},
year={1999},
}
Darya E. Apushkinskaya, and Aleksandr I. Nazarov. Linear two-phase Venttsel problems. 1999. Vol. 39. In Arkiv for Matematik. pp.201-222. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203601762758769.