1. Alferes, V. R. (2002). Programas e rotinas complementares do SPSS. Retrieved January 20, 2010, from http://www.fpce.uc.pt/nucleos/niips/
2. Amaral, L. (1994). Um referencial para o planeamento de sistemas de informação. Unpublished doctoral dissertation, University of Minho, Portugal.
3. Managing knowledge gives power.;J.Ash;Communication World,1998
4. Response Rate in Academic Studies-A Comparative Analysis
5. Harnessing the power of intellectual capital.;L. J.Bassie;Training & Development,1997