@inproceedings{yann2007diophantine,
title={Diophantine exponents for mildly restricted approximation},
author={Yann Bugeaud, and Simon Kristensen},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203624946182957},
booktitle={Arkiv for Matematik},
volume={47},
number={2},
pages={243-266},
year={2007},
}

Yann Bugeaud, and Simon Kristensen. Diophantine exponents for mildly restricted approximation. 2007. Vol. 47. In Arkiv for Matematik. pp.243-266. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203624946182957.