4Anderson, J. E., E. van Wincoop, 2003) "Gravity with Gravitas: A Solution to the Border Puzzle," Ameri- can Economic Review 93(1), 170-192.
5Chaney, T., 2008) "Distorted Gravity: The Intensive and Extensive Marginsof International Trade," Ameri- can Economic Review 98(4), 1707-1721.
6Clark, X., Dollar, D. and Micco, A., 2004) "Port Efficiency, Maritime Transport Costs and Bilateral Trade," Journal of Development Economics 75(2), 417-450.
7Head, K., Mayer, T., and Ries, J., 2010) "The Erosion of Colonial Trade Linkages after Independence," Journal of International Economics 81(I), 1-14.
