Saputra, Rendi Yuli, et al. “Perbandingan Karakteristik Asap Cair Pada Berbagai Grade Dari Pirolisis Batubara”. Jurnal Engineering, vol. 2, no. 2, Dec. 2020, pp. 96-108, https://online-journal.unja.ac.id/JurnalEngineering/article/view/11531.