Derudder, B. / 2005 / An appraisal of the use of air route data in assessing the world city network: A research note on data / Urban Studies 42 : 2371 ~ 2388 Ida, H. / 1993 / The Pattern of Passenger Flow in Japan / The Association of Japanese Geographers 66 (1) : 18 ~ 34 Keeling, D. / 1995 / Transport and the world city paradigm, In World Cities in a World-System / Cambridge Univ. Press : 115 ~ 131 Lee. H. S. / 2008 / The structure of the international air network through the social network analysis / Journal of Geography 117 (6) : 985 ~ 996 Lee. H. S. / 2009 / The networkability of cities in the international air passenger flows 1992-2004 / Journal of Transport Geography 17 (3) : 166 ~ 175