López-Salazar Rubén, González-Cervantes Guillermo, Vázquez-Alvarado Rigoberto Eustacio, Olivares-Sáenz Emilio, Juan Antonio Vidales-Contreras, Roberto Carranza de la Rosa, and Manuel Ortega-Escobar. 2018. “Humic and Fulvic Acid Extraction Method and Characterization by Infrared Spectrophotometry”. Revista Mexicana De Ciencias Agrícolas, no. 8 (April): 1397-1407. https://doi.org/10.29312/remexca.v0i8.1094.