Giraldo Estrada, Catalina, et al. “Application ZERI Methodology in the Production of Alkaline Protease from Bacillus Sp”. Revista Universidad EAFIT, vol. 39, no. 132, June 2012, pp. 57-64, https://publicaciones.eafit.edu.co/index.php/revista-universidad-eafit/article/view/895.