Columbia subject headings:
Harvard subject headings:
Zhenping Xian (Henan Sheng, China)--Economic conditions.
Zhenping Xian (Henan Sheng, China)--Social conditions.
Princeton subject headings:
Zhenping Xian (Henan Sheng, China)--Economic conditions.
Zhenping Xian (Henan Sheng, China)--Social conditions.