[1] Barber M J, Scherngell T, 2013. Is the European R&D network homogeneous? Distinguishing relevant network communities using graph theoretic and spatial interaction modelling approaches. Regional Studies, 47(8): 1283-1298. doi: 10.1080/ 00343404.2011.622745.
[2] Ben Letaifa S, Rabeau Y, 2013. Too close to collaborate? How geographic proximity could impede entrepreneurship and innovation. Journal of Business Research, 66(10): 2071-2078. doi: 10.1016/j.jbusres.2013.02.033.
[3] Boschma R A, Frenken K, 2010. The spatial evolution of innovation networks: a proximity perspective. In: Boschma R A et al. (eds.). Handbook of Evolutionary Economic Geography. Cheltenham: Edward Elgar, 120-135.
[4] Bourne L S, 1975. Urban Systems: Strategies for Regulation. Oxford: Oxford University Press, 26-50.
[5] Burt R S, 1992. Structural Holes: the Social Structure of Competition. Cambridge, Mass: Harvard Business School Press, 3-40.
[6] Camagni R P, Capello R, 2004. The city network paradigm: Theory and empirical evidence. In: Capello R et al. (eds.). Urban Dynamics and Growth. Netherlands: Elsevier B.V., 1-10.
[7] Castells M, 1989. The Information City. Oxford: Basil Blackwell, 3-8.
[8] Choi J H, Barnett G A, Chon B S, 2006. Comparing world city networks: A network analysis of Internet backbone and air transport intercity linkages. Global Networks-a Journal of Transnational Affairs, 6(1): 81-99. doi: 10.1111/j.1471-0374. 2006.00134.x.
[9] Dai Teqi, Jin Fengjun, 2008. Spatial interaction and network structure evolvement of cities in terms of China's rail passenger flows. Chinese Geographical Science, 18(3): 206-213. doi:  10.1007/s11769-008-0206-2.
[10] Derudder B,Witlox F, 2005. An appraisal of the use of airline data in assessing the world city network: a research note on data. Urban Studies, 42(13): 2371-2388. doi: 10.1080/004209805 00379503.
[11] Eslami H, Ebadi A, Schiffauerova A, 2013. Effect of collaboration network structure on knowledge creation and technological performance: the case of biotechnology in Canada. Scientometrics, 97(1): 99-119. doi:  10.1007/s11192-013-1069-6.
[12] Esparza A X, Krmenec A J, 2000. Large city interaction in the US urban system. Urban Studies, 37(4): 691-709. doi:  10.1080/00420980050003973.
[13] Fischer M M, Scherngell T, Jansenberger E, 2006. The geography of knowledge spillovers between high-technology firms in Europe: Evidence from a spatial interaction modeling perspective. Geographical Analysis, 38(3): 288-309. doi: 10. 1111/j.1538-4632.2006.00687.x
[14] Hou H, Kretschmer H, Liu Z, 2008. The structure of scientific collaboration networks in Scientometrics. Scientometrics, 75(2): 189-202. doi:  10.1007/s11192-007-1771-3.
[15] Jacobs W, Ducruet C, De Langen P, 2010. Integrating world cities into production networks: the case of port cities. Global Networks-a Journal of Transnational Affairs, 10(1): 92-113. doi:  10.1111/j.1471-0374.2010.00276.x
[16] Lei X P, Zhao Z Y, Zhang X et al., 2013. Technological collaboration patterns in solar cell industry based on patent inventors and assignees analysis. Scientometrics, 96(2): 427-441. doi:  10.1007/s11192-012-0944-x
[17] Leng Bingrong, Yang Yongchun, Li Yingjie et al., 2011. Spatial characteristics and complex analysis: a perspective from basic activities of urban networks in China. Acta Geographica Sinica, 2(66): 199-211. (in Chinese).
[18] Leydesdorff L, Persson O, 2010. Mapping the Geography of science: distribution patterns and networks of relations among cities and institutes. Journal of the American Society for Information Science and Technology, 61(8): 1622-1634. doi:  10.1002/Asi.21347
[19] Liefner I, Hennemann S, 2011. Structural holes and new dimensions of distance: The spatial configuration of the scientific knowledge network of China¢s optical technology sector. Environment and Planning A, 43(4): 810-829.
[20] Lu Luchang, Huang Ru, 2012. Urban hierarchy of innovation capability and inter-city linkages of knowledge in post-reform China. Chinese Geographical Science, 22(5): 602-616. doi:  10.1007/s11769-012-0555-8
[21] Matthiessen C W, Schwarz A W, Find S 2002. The ups and downs of global research centers. Science, 297(5586): 1476-1477. doi:  10.1097/CCM.0b013e3181d16b00.
[22] Matthiessen C W, Schwarz A W, Find S, 2010. World cities of scientific knowledge: systems, networks and potential dynamics. An analysis based on bibliometric indicators. Urban Studies, 47(9): 1879-1897. doi:  10.1177/0042098010372683.
[23] Mo Huihui, Wang Jiaoe, Jin Fengjun, 2009. Identifying centrality in the air transportation network of China. Transportation and Geography, 2: 493-502. doi:  10.1371/journal.pone.0066732.
[24] Nascimbeni F, 2013. Collaborative knowledge creation in development networks: lessons learnt from a transnational. The Journal of Community Informatics, 9(3): 1-8.
[25] Neal Z, 2010. Refining the Air Traffic Approach to City Networks. Urban Studies, 47(10): 2195-2215. doi: 10.1177/ 0042098009357352
[26] Storper M, 1997. The Regional World: territorial Development in a Global Economy. New York: Guilford press. 3-25.
[27] Tang L, Hu G Y, 2013. Tracing the footprint of knowledge spillover: Evidence from U.S.: China collaboration in Nanotechnology. Journal of the American Society for Information Science and Technology, 64(9): 1791-1801. doi:  10.1002/Asi.22873
[28] Taylor P J, 2001. Specification of the world city network. Geographical Analysis, 33(2): 181-194.
[29] Taylor P J, Catalano G, Walker D R F, 2002. Measurement of the world city network. Urban Studies, 39(13): 2367-2376.
[30] Thompson P, Fox-Kean M, 2005. Patent citations and the geography of knowledge spillovers: a reassessment. American Economic Review, 95(1): 450-460. doi: 10.1257/00028280 53828509.
[31] Vinciguerra S, Frenken K,Valente M, 2010. The Geography of internet infrastructure: an evolutionary simulation approach based on preferential attachment. Urban Studies, 47(9): 1969-1984.
[32] Wallace R, Wallace D, Ullmann J E et al., 1999. Deindustriali­zation, inner-city decay, and the hierarchical diffusion of AIDS in the USA: how neoliberal and cold war policies magnified the ecological niche for emerging infections and created a national security crisis. Environment and Planning A, 31(1): 113-139. doi:  10.1068/A310113
[33] Wang J E, Mo H H, Wang F H et al., 2011. Exploring the network structure and nodal centrality of China's air transport network: A complex network approach. Journal of Transport Geography, 19(4): 712-721. doi: 10.1016/j.jtrangeo.2010. 08.012.
[34] Wasserman S, Faust K, 1994. Social Network Analysis: Methods and Applications. New York and Cambridge, ENG: Cambridge University Press.
[35] Zhen Feng, Wang Bo, Chen Yingxue, 2012. China's city network characteristics based on social network space: an empirical analysis of Sina Micro-blog. Acta Geographica Sinica, 67(8): 1031-1043. (in Chinese).
[36] Zhen Feng, Wang Xia, Yin Jun et al., 2013. An empirical study on Chinese city network pattern based on producer services. Chinese Geographical Science, 23(3): 274-285. doi: 10.1007/ s11769-013-0595-8.