1. Mihyeon Jeon, C., A.A. Amekudzi, and J. Vanegas, Transportation system sustainability issues in high-, middle-, and low-income economies: Case studies from Georgia (U.S.), South Korea, Colombia, and Ghana. Journal of Urban Planning and Development, 2006. 132(3): 172-186.
2. Frey, W.H., et al., Tracking Metropolitan America into the 21st Century: A Field Guide to the New Metropolitan and Micropolitan Definitions. 2004, Brookings Institution.
3. The 21st-Century Metropolis---New Geographies of Theory;Roy;Regional Studies,2009
4. Metropolitan governance;Newton;European Political Science,2012
5. Heinelt, H. and D. Kubler, Metropolitan Governance in the 21st Century: Capacity, Democracy and the Dynamics of Place. 2005, 2 Park Square, Miltom Park, Abingdon, Oxon OX14 4RN: Routledge.