http://chengjun.github.io/cn/2013/08/sna-book-chapter/
https://snap.stanford.edu/data/
http://blog.fens.me/hadoop-social-peoplerank/
https://sites.google.com/site/ucinetsoftware/downloads
http://www.rdatamining.com/examples/social-network-analysis
https://class.coursera.org/datavisualization-001/lecture
http://wx.shenchuang.com/article/2015-08-31/1168623.html
