1. Barker, P.G.: Author languages for CAL. London: Macmillan 1987
2. Barker, P.G.: KnowledgePro: A review and assessment, engineering applications of artificial intelligence, 2(4), pp. 325–338 (1989)
3. Barker, P.G.: Electronic books. Learning Resources Journal, 6(3), pp. 62–68 (1990)
4. Interactive Multimedia;PG Barker,1991
5. Barker, P.G.: Automatic code generators for hypermedia authoring. Working paper. Interactive Systems Research Group. School of Computing and Mathematics. Teeside Polytechnic. Cleveland, UK 1991b