“Efek Variasi Konsentrasi Zat Aktivator H3PO4 Terhadap Morfologi Permukaan Dan Gugus Fungsi Karbon Aktif Cangkang Kemiri: (The Effect of H3PO4 Variation on Morphology and Function Group of Activated Carbon of Hazelnut Shell)”. 2021. Gravitasi 20 (1): 19-23. https://doi.org/10.22487/gravitasi.v20i1.15519.