T. Sasikala, K. Greeshma, P. K. Gnana, S. Muthulingam, and C. Nandhakumar, “Synthesis, characterization and chelating properties of tannin-8-hydroxy quinoline - formaldehyde polymer”, GSC Adv. Res. Rev., vol. 5, no. 2, pp. 019–023, Nov. 2020.