APA (7th ed.) Citation

Garrison, D. R. (2011). E-learning in the 21st century: A framework for research and practice (2. ed.). Routledge.

Chicago Style (17th ed.) Citation

Garrison, D. Randy. E-learning in the 21st Century: A Framework for Research and Practice. 2. ed. New York [u.a.]: Routledge, 2011.

MLA (9th ed.) Citation

Garrison, D. Randy. E-learning in the 21st Century: A Framework for Research and Practice. 2. ed. Routledge, 2011.