@inproceedings{lars1965weighted,
title={Weighted mean square approximation in plane regions, and generators of an algebra of analytic functions},
author={Lars Inge Hedberg},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203433410259036},
booktitle={Arkiv for Matematik},
volume={5},
number={6},
pages={541-552},
year={1965},
}
Lars Inge Hedberg. Weighted mean square approximation in plane regions, and generators of an algebra of analytic functions. 1965. Vol. 5. In Arkiv for Matematik. pp.541-552. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203433410259036.