References
- Crystal, D. (1986) ISAAC in chains: The future of communication systems. Augmentative and Alternative Communication, 2, 140–145.
- Kraat, A. (1986). Developing intervention goals. In S. Blackstone & D. Bruskin, Augmentative communication: An introduction. Rock-ville, MD: ASHA.
- Yin, R. (1984). Case study research: design and methods. Beverly Hills, CA:SAGE Publications.