Cano Martínez, Carlos Andrés, et al. “Evaluation of Some Properties of Rocks Found in the Central Zone of the East Slope of Medellin”. Revista Universidad EAFIT, vol. 39, no. 130, June 2012, pp. 79-86, https://publicaciones.eafit.edu.co/index.php/revista-universidad-eafit/article/view/912.