Funding for this research was provided by:
Science Foundations of China University of Petroleum--Beijing (2462015BJB05, 2462015YQ0604, 2462015QZDX02)
Scientific Research Foundation for the Returned Overseas Chinese Scholars
Natioanl Science Foundation (DMS-1317994)
Dr. Walter Koss Professorship
Science Foundations of China University of Political Science and Law (1000-10816106, 1000-10816330)