Gaya APA
Thomas, L., Haryoko, S. (1980).
The East Kalimantan Coal Project Report On The Coal Geology Of Loa Kulu And Loa Haur .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
Thomas, L.P.., Haryoko, S..
"The East Kalimantan Coal Project Report On The Coal Geology Of Loa Kulu And Loa Haur".
Bandung:
Pusat Sumber Daya Geologi,
1980.
Batubara.