A. Keshavarz, Z. Parang, and A. Nasseri, “The effect of sulfuric acid, oxalic acid, and their combination on the size and regularity of the porous alumina by anodization”, J. Nanostruct. Chem., vol. 3, no. 1 (December 2013), May 2013, doi: 10.1186/2193-8865-3-34.