Z. Z. F. Alizar, M. Mawardi, A. Ulianas, S. Aini, and O. Suryani, “NiAl₂O₄ -Modified Glassy Carbon Electrode From Napa Soil For Pb²⁺ Ions Using Voltammetry”, HJKK, vol. 14, no. 3, pp. 508–516, Jun. 2026.