Gaya APA

Wiyarsih, . et al (2011). Natural gas as petroleum fuel substitution: analysis of supply-demand projections, infrastructures, investments and-user prices (Vol. 15, No. 1, Tahun). : American foundations information service.

Gaya MLA

Wiyarsih, . et al. "Natural gas as petroleum fuel substitution: analysis of supply-demand projections, infrastructures, investments and-user prices". Vol. 15, No. 1, Tahun : American foundations information service, 2011. Text.