Pernía, Beatriz, Mariuxi Mero, Kenya Bravo, Nelson Ramírez, David López, Jorge Muñoz, and Fidel Egas. 2015. “The Cadmium and Lead Levels in cow´s Milk Marketed in the City of Guayaquil, Ecuador”. Revista Científica Ciencias Naturales Y Ambientales 8 (2):6. https://doi.org/10.53591/cna.v8i2.221.