zachary karate club:
http://konect.uni-koblenz.de/networks/ucidata-zachary
http://konect.uni-koblenz.de/downloads/ucidata-zachary.tar.bz2
http://proj.ise.bgu.ac.il/sns/students.html
http://proj.ise.bgu.ac.il/sns/datasets/students.zip
http://snap.stanford.edu/data/email-Enron.html
http://snap.stanford.edu/data/email-Enron.txt.gz
Weighted network:
http://konect.uni-koblenz.de/networks/opsahl-usairport
http://konect.uni-koblenz.de/downloads/opsahl-usairport.tar.bz2
