Gaya APA
Project, W, C, O, C, S, C, E. (1989).
Report on Detailed and Semi Detailed Exploration of Central Sumatra Coal Exploration Project Appendix VI Geotechnical Analysis .
Bandung:
Pusat Sumber Daya Geologi.
Gaya MLA
Project, Working, Commitee, Of, Central, Sumatera, Coal, Eksploration.
"Report on Detailed and Semi Detailed Exploration of Central Sumatra Coal Exploration Project Appendix VI Geotechnical Analysis".
Bandung:
Pusat Sumber Daya Geologi,
1989.
Batubara.