7Granovetter, M. 1973, The Strength of Wead Ties, American Journal of Sociology, 1978.
8Mithell, J. Clyde, 1969, The Concept and Use of Social Network, in Social Network in Urban Situations,edited by J. C. Mithell. Manchester, Eng: ManchesterUniversityPress.
9Lin, Nan. 1982, Social Resources and Instrnmental Action, in Marsden, P. and Lin, Nan. ( eds), Social Strncture and Network Analysis, Beverly Hills, CA : Sage Publication, Inc.
10Williamson, O. 1975, Markets and Hierarchies Analysis and Antitrust Implications, New York: Free Press.