Rumiyanti L, Listiani L, Damayanti T. OPTIMIZATION OF THE USE OF FLY ASH AS AN ADDITIVE PORTLAND COMPOSITE CEMENT (PCC). SPEKTRA [Internet]. 2019 Aug. 31 [cited 2024 Nov. 22];4(2):61-72. Available from: https://journal.unj.ac.id/unj/index.php/spektra/article/view/10035