1. Asteroff, J.F.: Paralanguage in electronic mail: a case study. Ph.D. thesis, Columbia University New York (1987)
2. Belo, C., Caridade, H., Cabral, L., Sousa, R.: Deficiência intelectual: terminologia e conceptualização. Revista Diversidades 22, 4–9 (2008)
3. Alan, H.R.: A three cycle view of design science research. Scand. J. Inf. Syst. 19(2), 4 (2007)
4. Cybis, W., Holtz, A., Faust, R.: Novatec, Ergonomia e usabilidade. São Paulo (2010)
5. Luckasson, R., et al.: Mental retardation: definition, classification, and systems of supports. American Association on Mental Retardation (2002)