Medina Saavedra, T., Arroyo Figueroa, G. and Peña Caballero V. 2018. Chromatography of Pfaiffer in the analysis of soils of productive systems. Revista Mexicana de Ciencias Agrícolas. 9, 3 (May 2018), 665–673. DOI:https://doi.org/10.29312/remexca.v9i3.1223.