A. V. Ganorkar, S. S. Askarkar, K. R. Gupta, and M. J. Umekar, “Validated Stability Indicating and Assay Method Development of Linagliptin in Formulation by RP-HPLC Using Quality by Design”, Orbital: Electron. J. Chem., vol. 12, no. 2, pp. 48-61, Jun. 2020.