Prevalence and socio-demographic correlates of major depressive disorder in older adults in Hebei province, China. - Zhang, Yun-Shu; Jin, Yu; Rao, Wen-Wang; Cui, Li-Jun; Li, Jian-Feng; Li, Lin; Ungvari, Gabor S.; Hall, Brian J.; Li, Ke-Qing; Xiang, Yu-Tao (Journal of Affective Disorders, 2020)