El-Bagary, R. I., Elkady, E. F. and Ayoub, B. M. (2013) “Development and validation of a reversed phase liquid chromatographic method for the determination of three Gliptins and Metformin in the presence of Metformin impurity (1-cyanoguanidine)”, European Journal of Chemistry, 4(4), pp. 444–449. doi: 10.5155/eurjchem.4.4.444-449.844.