Ning, J. et al. 2014. Vortex-Assisted Surfactant-Enhanced Emulsification Microextraction Combined with High Performance Liquid Chromatography-Fluorescence Detector for Determination of Nitrite in Urine. Asian Journal of Chemistry. 26, 21 (Sep. 2014), 7129–7132. DOI:https://doi.org/10.14233/ajchem.2014.16523.