SHAH, Syed Farman Ali et al. Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry. Pakistan Journal of Analytical & Environmental Chemistry, [S.l.], v. 16, n. 2, p. 9, june 2015. ISSN 2221-5255. Available at: <http://pjaec.pk/index.php/pjaec/article/view/116>. Date accessed: 10 aug. 2022.