Gaya APA

Purba, J, B. et al (2007). Biodesulphurization within natural gas in oil and gas field (Vol. 11, No. 1, Tahun). : American foundations information service.

Gaya MLA

Purba, Jasawitten, Brando. et al. "Biodesulphurization within natural gas in oil and gas field". Vol. 11, No. 1, Tahun : American foundations information service, 2007. Text.