HERRERA, A. B. et al.
Highly Active Absorbent for SO₂ Removal Prepared from Coal Ash (Part 3).
Philippine Engineering Journal, [S.l.], v. 20, n. 1, aug. 2021.
ISSN 2718-9287.
Available at: <https://journals.upd.edu.ph/index.php/pej/article/view/8009>. Date accessed: 18 sep. 2025.