References
- Garrison , D. 1985 . Three generations of technological innovation in distance education . Distance Education , 6 (2) : 235 – 41 .
- Keegan , D. 1990 . Foundations of distance education , London : Routledge. 2nd Edition .
- Keegan , D. 1993 . Very large distance education systems , Hagen : FernUniversität (ZIFF) .
- OECD . 1997 . OECD Communications Outlook 1997 http:www.oecd.org/dsti/commhigh.html
- Peters , O. 1966 . Das Hochschulfernstudium (University‐level distance education) , Weinheim : Beltz .
- Peters , O. , ed. 1971 . Texte zum Hochschulfernstudium (University‐level distance education texts) , 7 – 25 . Weinheim : Beltz .