V.S. Nirogi, Ramakrishna, et al. “Design, Synthesis and Biological Evaluation of Novel Benzopyran Sulfonamide Derivatives As 5-HT6 Receptor Ligands”. Asian Journal of Chemistry, vol. 27, no. 6, Mar. 2015, pp. 2117-24, doi:10.14233/ajchem.2015.17783.