5ELLISON G, GLAESER E. Geographic concentration in US manufacturing industries: A dartboard approach [ J ]. Journal of Political Economy, 1997,105 (5) :28-32.
6国民经济行业分类[S].北京:中国标准出版社,2007.
7Ellison,G.and Glaeser,E.(1997).Geographic concentration in US manufacturing industries:A dartboard approach.Journal of Political Economy.
8.中国工业经济统计年鉴[M].北京:中国统计出版社,2004年..
9《陕西统计年鉴》(2005).
10Luxembourg. Innovative Hot Spots in Europe: policies to promote trans-border clusters of creative activity[J]. Trend Chart Policy Workshop,Background Paper on Methods for Cluster Analysis, May 5-6, 2003.