Sofyan, Sofyan, et al. “Natural Liquid Dyestuff from Wastewater of Gambier Processing (Uncaria Gambir Roxb) As Textile Dye”. International Journal on Advanced Science, Engineering and Information Technology, vol. 10, no. 6, Dec. 2020, pp. 2512-7, doi:10.18517/ijaseit.10.6.12891.