SRINIVASAN, R., and A.N. MOHAMED KASIM. “Cooxidation of Aromatic Anils and Oxalic Acid by Chromic Acid in Aqueous Acetic Acid Medium”. Asian Journal of Chemistry, vol. 21, no. 9, Mar. 2010, pp. 6909-14, https://asianpubs.org/index.php/ajchem/article/view/12163.