@inproceedings{anders1964on,
title={On iterated functions with asymptotic conditions at a fixpoint},
author={Anders Lundberg},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203430482247011},
booktitle={Arkiv for Matematik},
volume={5},
number={3},
pages={193-206},
year={1964},
}
Anders Lundberg. On iterated functions with asymptotic conditions at a fixpoint. 1964. Vol. 5. In Arkiv for Matematik. pp.193-206. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203430482247011.