Granovetter, M. : The Strength of Weak Ties, American Journal of Sociology, Vol.78, No.6, pp.1360-1380 (1973).
Ioannidis, S. and Chaintreau, A. : On The Strength of Weak Ties in Mobile Social Networks, Proceedings of The Second ACM EuroSys Workshop on Social Network Systems, pp.19-25 (2009).