A. Rodrigues and J. Gluz. " SAAPIEnS: A Tool for Authoring Learning Objects and Pedagogical Support in Natural Deduction for Propositional Logic", in Proceedings of the 8th Workshop-School on Agents, Environments, and Applications, Porto Alegre/RS, 2014, pp. 209-214, doi: https://doi.org/10.5753/wesaac.2014.33304.