Gaya APA

indonesia, P, P, S, I. (1974). feasibility report on ombilin coal mine prepared for perusahaan negara tambang batubara . : P.T. Petro - Sea Interational Indonesia.

Gaya MLA

indonesia, P.t, Petro, Sea, International. "feasibility report on ombilin coal mine prepared for perusahaan negara tambang batubara". : P.T. Petro - Sea Interational Indonesia, 1974. Text.