Purwaningsih, Ratna, Christoper Frans Simanjuntak, and Zainal Fanani Rosyada. “Eco-Efficiency of Pencil Preduction Using Life Cycle Assessment to Increase the Manufacture Sustainability”. Jurnal Teknik Industri: Jurnal Keilmuan dan Aplikasi Teknik Industri 22, no. 1 (June 16, 2020): 47-54. Accessed April 18, 2024. https://jurnalindustri.petra.ac.id/index.php/ind/article/view/22504.