@inproceedings{andrea2014the,
title={The convergence Newton polygon of a$p$-adic differential equation I: Affinoid domains of the Berkovich affine line},
author={Andrea Pulita},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203405003739802},
booktitle={Acta Mathematica},
volume={214},
number={2},
pages={307-355},
year={2014},
}

Andrea Pulita. The convergence Newton polygon of a$p$-adic differential equation I: Affinoid domains of the Berkovich affine line. 2014. Vol. 214. In Acta Mathematica. pp.307-355. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203405003739802.