Oyagi, M. O., J. O. Onyatta, G. N. Kamau, and P. M. Guto. “Simultaneous Determination of Trace Lead (II), Cadmium (II) and Cobalt (II) by Differential Pulse Anodic Stripping Voltammetry Using Polyacrylic acid/Glassy Carbon Electrode”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 23, no. 2, July 2015, pp. 324-3, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/4309.