dos Santos, T. de A. D.; da Costa, D. O.; Pita, S. S. da R.; Semaan, F. S. Potentiometric and Conductimetric Studies of Chemical Equilibria for Pyridoxine Hydrochloride in Aqueous Solutions: Simple Experimental Determination of PKa Values and Analytical Applications to Pharmaceutical Analysis. Eclet. Quim. 2010, 35, 81-86.