Berti, Juliana Pereira, and Laurete Teresinha Zanol Sauer. “Making and Understanding Analytic Geometry Using the Software Geogebra”. Scientia Cum Industria, vol. 3, no. 3, Feb. 2016, pp. 120-2, https://sou.ucs.br/etc/revistas/index.php/scientiacumindustria/article/view/4111.