Saborío-Montero, A., Marín-Taylor, O., Arguedas-Sánchez, R. and Ramírez-Fallas, S. (2015) “Soil chemical fertility in dairy farms of the Guanacaste volcanic mountain range, Costa Rica”, UNED Research Journal, 7(2), pp. 157–163. doi: 10.22458/urj.v7i2.1140.