https://mirrors.tuna.tsinghua.edu.cn/CRAN/ TUNA Team, Tsinghua University

http://mirrors.tuna.tsinghua.edu.cn/CRAN/ TUNA Team, Tsinghua University

https://mirrors.ustc.edu.cn/CRAN/ University of Science and Technology of China

http://mirrors.ustc.edu.cn/CRAN/ University of Science and Technology of China

https://mirrors.eliteu.cn/CRAN/ Elite Education

https://mirror.lzu.edu.cn/CRAN/ Lanzhou University Open Source Society

http://mirror.lzu.edu.cn/CRAN/ Lanzhou University Open Source Society

https://mirrors.tongji.edu.cn/CRAN/ Tongji University