D. BHOSALE, VIDHYA, et al. “Potentiometric Determination of Formation Constants of Metal Ion Complexes With Schiff Bases of 4,5-Dimethyl Salicylaldehyde”. Asian Journal of Chemistry, vol. 16, no. 1, June 2010, pp. 338-42, https://asianpubs.org/index.php/ajchem/article/view/19619.