Title: Zhong yuan jing ji qu bao rong xing zeng zhang lu jing yan jiu
Subjects: Economic development, Economic conditions
Places: China, Henan Sheng, Hebei Sheng, Shanxi Sheng, Shandong Sheng, Henan Sheng (China), Hebei Sheng (China), Shanxi Sheng (China), Shandong Sheng (China)
Time periods: 21st century