@article{Rentroia08c&c,
  title={Evaluating Learning Support Systems Usability An Empirical Approach},
  author={Rentr{\'o}ia-Bonito, A. and Guerreiro, T. and Martins, A. and Fern, V. and Jorge, J.},
  journal={Communication \& cognition. Monographies},
  volume={41},
  number={1-2},
  pages={143--158},
  year={2008},
  publisher={Communication and cognition}
}