@inproceedings{weizhu2021uniform,
title={Uniform error bounds of time-splitting spectral methods for the long-time dynamics of the nonlinear Klein–Gordon equation with weak nonlinearity},
author={Weizhu Bao, Yue Feng, and Chunmei Su},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20220519155500863152282},
booktitle={Mathematics of Computation},
volume={91},
pages={811-842},
year={2021},
}

Weizhu Bao, Yue Feng, and Chunmei Su. Uniform error bounds of time-splitting spectral methods for the long-time dynamics of the nonlinear Klein–Gordon equation with weak nonlinearity. 2021. Vol. 91. In Mathematics of Computation. pp.811-842. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20220519155500863152282.