1. Agresti, A. 2013. Categorical Data Analysis. New York: Wiley.
2. Akousmaflore. 2007. “Scenocsme: Grégory Lasserre & Anaïs met den Ancxt.” Akousmaflore. Accessed May 10. http://www.scenocosme.com/akousmaflore_en.htm.
3. Likert Scales and Data Analyses;Allen I. E.;Quality Progress,2007
4. Bentler, P. M. 1995. EQS Structural Equations Program Manual. 1st ed. California: Multivariate software.
5. Boar, B. H. 1984. Application Prototyping: A Requirements Definition Strategy for the 80‘s. New York: Wiley.