1、Energy consumption, carbon emissions, and economic growth in China
      Zhang, Xing-Ping and Cheng, Xiao-Mei
2、CO2 emissions, energy usage, and output in Central America
      Nicholas Apergis and James E. Payne
3、Causal relationship between energy consumption and GDP growth revisited: A dynamic panel data approach
      Huang, Bwo-Nung, M.J. Hwang and C.W. Yang
  请各位大侠帮忙啊