6Collis, B.(1996). Tele-Leaming in a Digital World: The Future of Distance Learning[M]. Boston: International ThomsonComputer Press: 1-9.
7Medel-Afionuevo, C., Ohsako, T., & Mauch, W.(2001). Revisiting Lifelong Learning for the 21st Century[EB/OL]. [2015-10-20]. http://www.unesco.org/education/uie/pdf/revisit- ingLLL.pdf.
8Mills, R., & Tain, A.(1996). Supporting the Learner in Open and Distance Learning[M]. London: Pitman Publishing: 8-12.
9Siemens, G.(2005). Connectivism: A Learning Theory for the Digital Age[J]. International Journal of Instructional Technology & Distance Learning, 2: 3-10.
10Steffens, K.(2015). Competences, Learning Theories and MOOCs: Recent Developments in Lifelong Learning[J]. European Journal of Education, 50 (1): 41-59.