Tan, R. G. R. dan Culaba, B. (2004) “Net Energy and Carbon Flow Analyses on four pathways for the utilization of Natural Gas as Automotive Fuel”, 4(1), hlm. 33-38. Tersedia pada: https://jurnal.ugm.ac.id/v3/AJChE/article/view/7585 (Diakses: 8Juni2025).