Ramos, A., y V. Callao. «Study of the Microbial Mobilization of Phosphates in the Soil by Percolation». Ars Pharmaceutica (Internet), vol. 8, n.º 11-12, octubre de 1967, pp. 473-6, https://revistaseug.ugr.es/index.php/ars/article/view/7687.