2Alex Hoen , Three Variations on Identifying Clusters, Paper presented at the OECD- workshop on cluster Analysis and Cluster based Policy. Amsterdam, (1997).
3Gordon, I.R. and Mc Cann, P. Industrial Clusters: Complexes,Agglomeration and/or Social Networks? Urban Studies, (2000).
4Arrow, K. J. Increasing Returns and Economic Analysis. S.T.Martin's Press, (1998).