4Hakansson, N. Portfolio analysis[M] // Eatwell, J., Milgate, M., Newman, P. The new palgrave: A dictionary of economics. London: Macmillan, 1987:917-920.
5Meeus, M.T.H., Oerlemans, L.A.G., Hage, J. Patterns of interactive learning in a high-tech region: An empirical exploration of an extended resource-based model[J]. Organization Studies, 2001, 22(1): 145-172.
6Porter, M. Locations, clusters, and company strategy[M]. The Oxford Handbook of Economic Geography. Oxford: Oxford University Press, 2000:253-274.
7Newman, M.E.J. The structure and function of complex networks[J]. SIAM Review, 2003, 45(2): 167-256.
8Ravasz, E.A., Somera, L., Mongru, D.A., et al. Hierarchical organization of modularity in metabolic networks[J]. Science, 2002, 297(5586): 1551-1555.
9Zhou, T., Yan, G., Wang, B.H. Maximal planar networks with large clustering coefficient and power-law degree distribution[J]. Physical Review E, 2005, 71:1-13.
10Takeda, Y., Kajikawa, Y., Sakata, I., et al. An analysis of geographical agglomeration and modularized industrial networks in a regional cluster: A case study at Yamagata prefecture in Japan[J]. Technovation, 2008, 28(8): 531-539.
