Bathula, Surendra Bose, et al. “Chitosan-SO3H: A Green Approach to 2-Aryl Heteroaryl Benzothiazoles under Solvent-Free Conditions at Room Temperature”. Asian Journal of Chemistry, vol. 30, no. 7, May 2018, pp. 1512-6, doi:10.14233/ajchem.2018.21209.