Yoon, Hyun-Ah, et al. “Synthesis and Antiviral Activity of Some 1H-Pyrrolo[3,2-b]pyridin-6-yl)acetic Acid Derivatives”. Asian Journal of Chemistry, vol. 29, no. 6, Apr. 2017, pp. 1199-05, doi:10.14233/ajchem.2017.20372.