1. Eyes on the horizon, feet on the ground;Heppel,1993
2. Developing interactive courseware and networks: some current issues;Romiszowski,1993
3. Hypertext and Hypermedia;Nielson,1990
4. The textbook of the future;Cunningham,1993
5. Constructivism: new implications for educational technology?;Duffy;Educ. Technol.,1991