https://github.com/brenden17/clustring-docs
- http://archives.knowhow.or.kr/archives/index.php?bId=437&speechId=747
- http://www1.president.go.kr/president/speech.php
- http://scikit-learn.org/stable/auto_examples/applications/topics_extraction_with_nmf.html
- http://radimrehurek.com/gensim/index.html
- http://www.stanford.edu/group/mmds/slides2012/s-park.pdf