Abbasi, K.U., M.Y. Khuhawar, K.P. Mahar, Arfana Mallah, and A. Nawaz Siyal. 2012. “Gas Chromatographic Determination of α-Keto Acids in Pharmaceutical Preparation Using 1,2-Propylenediamine As Derivatizing Reagent”. Asian Journal of Chemistry 25 (3):1211-15. https://doi.org/10.14233/ajchem.2013.12367.