Hanneman, R.A. and Riddle, M. (2005) Introduction to Social Network Methods. http://faculty.ucr.edu/~hanneman/nettext/
 Xiang, R., Neville, J. and Rogati, M. (2010) Modeling Relationship Strength in Online Social Networks. Proceedings of the 19th International Conference on World Wide Web, 981-990. http://dx.doi.org/10.1145/1772690.1772790
 Srba, I. and Bielikova, M. (2010) Tracing Strength of Relationships in Social Networks. 2010 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology, Toronto, 31 August-3 September 2010, 13-16.
 Yanagimoto, H. and Yoshioka, M. (2012) Relationship Strength Estimation for Social Media Using Folksonomy and Network Analysis. WCCI 2012 IEEE World Congress on Computational Intelligence, Brisbane, 10-15 June 2012, 1-8.