Gaya APA
al, R, C, E. (1971).
Final Report 1970-1971 Recconaissance concession block 10 and 11 sumatera, Indonesia .
Jakarta:
P.T. Cennecott.
Gaya MLA
al, R.E, Clynch,, Et.
"Final Report 1970-1971 Recconaissance concession block 10 and 11 sumatera, Indonesia".
Jakarta:
P.T. Cennecott,
1971.
Logam.