1DeBoer J, Ho A D, Stump G S, et al. Changing "Course":Reconcep- tualizing Educational Variables for Massive Open Online Courses [J]. Educational researcher,2014(2) :74-84.
2Hedberg J G. E-learning futures? Speculations for a time yet to come[J].Studies in Continuing Education,2006(2) :171-183.
3Unesco. Youth and skills: Putting education to work[G]//EFA Global Monitoring Report. New York : Unesco, 2012.