Valdueza, Johanna Andrea, et al. “Method Development and Validation of Gas Chromatography Methods Using Nitrogen Phosphorus Detector (GC-NPD) and Isotope Dilution Triple Quadrupole Mass Spectrometry (GC-IDMS MS) for the Determination of Chlorpyrifos in Mango”. KIMIKA: The Journal of the Kapisanang Kimika Ng Pilipinas, vol. 33, no. 1, Mar. 2022, pp. 1-8, doi:10.26534/kimika.v33i1.1-8.