http://en.wikipedia.org/wiki/Network_theory

http://en.wikipedia.org/wiki/Social_network

http://en.wikipedia.org/wiki/Actor_network_theory

http://en.wikipedia.org/wiki/Complex_network

http://www.chass.utoronto.ca/~wellman/publications/index.html

http://www.si.umich.edu/~rfrost/courses/SI110/readings/In_Out_and_Beyond/Granovetter.pdf

http://www.stanford.edu/dept/soc/people/mgranovetter/documents/granstrengthweakties.pdf

http://www.ucm.es/info/pecar/Articulos/GRANOVETTER2.pdf (en espaņol)

Mark Granovetter. "The Strength of Weak Ties: a network theory 
revisited"; American Journal of Sociology, Vol. 78, No. 6., May 1973, 
pp 1360-1380