Deveoglu, O., et al. “Identification of Dyestuffs in the Natural Pigments Produced With Al3+, Fe2+ and Sn2+ Mordant Metals from Cochineal (Dactylopius Coccus Costa) and Walloon Oak (Quercus Ithaburensis Decaisne) by HPLC-DAD”. Asian Journal of Chemistry, vol. 22, no. 9, July 2010, pp. 7021-30, https://asianpubs.org/index.php/ajchem/article/view/11943.