https://www.coursera.org
https://www.edx.org
https://www.udemy.com
https://www.udacity.com/
https://xuetangx.com/
https://www.futurelearn.com/
http://cnx.org/
http://ocw.nthu.edu.tw/ocw/
http://ocw.mit.edu/index.htm
http://webcast.berkeley.edu/
http://www.skilledup.com/
https://brilliant.org/
http://mooc.guokr.com/
https://www.khanacademy.org/
https://www.youtube.com/channel/UC3yA8nDwraeOfnYfBWun83g
http://oyc.yale.edu/
http://oli.cmu.edu/
http://www.extension.harvard.edu/open-learning-initiative
http://grou.ps/oercenter
