Gaya APA

Purwnto, A, Q, T, A, W, W. (). Natural gas as petrolium fuel substitution:investments and user prices . : .

Gaya MLA

Purwnto, Abdul, Qoyum, Tjandranegara,, Arsegianto,, Widodo, Wahyu. "Natural gas as petrolium fuel substitution:investments and user prices ". : , . .