Distance education as two-way communication : essays in honour of Börje Holmberg /
edited by Gerhard E. Ortner, Kurt Graff, and Harald Wilmersdoerfer.
- Gerhard E. Ortner, Kurt Graff, and Harald Wilmersdoerfer.
- Frankfurt am Main ; New York : P. Lang, c1992.
- xx, 272 p. ; 23 cm.