M.Z.A, Y., A. A.M.M, P. R, Y. R, Y. M. M.A, and A. A.K. “Zn 2P₁/â‚‚ and Zn 2P₃/â‚‚ Electron Binding Energies With Nitrogen in Chitosan-Zinc Acetate Membranes Determined by X-Ray Photoelectron Spectroscopy Studies”. Malaysian Journal of Science, vol. 21, Dec. 2002, pp. 169-71, http://mojes.um.edu.my/index.php/MJS/article/view/8882.