7The polycentric metropolis:learning from mega-city regions in Europe [ M ]. London: Routledge, 2006.
8Matsumoto H. International urban systems and air passenger and cargo flows:some calculations [ J ]. Journal of Air Transport Management, 2004,10(4): 239 - 247.
9Goddard J B. Functional regions within the city centre: a study by factor analysis of taxi flows in central London [J]. Transac- tions of the Institute of British Geographers, 1970,49:161 - 182.
10De Montis A, Barthelemy M, Chessa A, et al. The structure of Inter- Urban traffic: A weighted network analysis [ J ]. Environ-ment and Planning: B, 2007,34(5): 905 - 924.
