Sahu, G.P., and S.C. Lavale. “Bromopyrogallol Red: A New Microanalytical Reagent for Amperometric Estimation of Dy(III) and Gd(III)&Dagger”;. Asian Journal of Chemistry, vol. 12, no. 1, Mar. 2010, pp. 203-6, https://asianpubs.org/index.php/ajchem/article/view/22905.