References
- http://en.wikipedia.org/wiki/Association_rule_learning#FP-growth_algorithm
- http://www.acc.ncku.edu.tw/chinese/faculty/shulc/courses/adb/data-streams/Han-frequent-patterns-without-candidate-generation.pdf
- http://cgi.csc.liv.ac.uk/~frans/KDD/Software/FPgrowth/fpGrowth.html
- http://www.cis.hut.fi/Opinnot/T-61.6020/2008/fptree.pdf
- http://algo.kangnung.ac.kr/~hblee/papers/06-kips-fptree.pdf