Niu Xiao-Xi, Sun Ren-Hua, Liu Zhao-Hui, Bai Yao-Hui, Xiao Bing-Bing
Department of Obstetrics and Gynecology, Peking University First Hospital, Beijing 100034, China.
Rural Energy and Environment Agency, Ministry of Agriculture, Beijing, China.
Chin Med J (Engl). 2018 Sep 20;131(18):2242-2243. doi: 10.4103/0366-6999.240801.