@inproceedings{renjun2005time,
title={Time periodic solutions of the Navier-Stokes equations in unbounded cylindrical domains---Leray's problem for periodic flows},
author={Renjun Duan, Seiji Ukai, Tong Yang, and Huijiang Zhao},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224211243520567583},
booktitle={Communications in Mathematical Physics},
volume={277},
pages={189-236},
year={2005},
}

Renjun Duan, Seiji Ukai, Tong Yang, and Huijiang Zhao. Time periodic solutions of the Navier-Stokes equations in unbounded cylindrical domains---Leray's problem for periodic flows. 2005. Vol. 277. In Communications in Mathematical Physics. pp.189-236. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191224211243520567583.