Political ecology and social development in the south of Yuan and Ming dynasties 并列题名：Political ecology and social development in the south of Yuan and Ming dynasties Population and social development in the process of opening up Road to economic and social development in the Tumen River region of China Theoretical and practical development of community covenants in Ming and Qing dynasties 并列题名：Theoretical and practical development of community covenants in Ming and Qing dynasties