Gaya APA
COLLIER, W., WERDAJA, S, T.
(1972).
Smallholder Rubber :
.
Canberra:
Australian national university.
Gaya MLA
COLLIER, W.., WERDAJA, Suhud, Tjakra.
"Smallholder Rubber :".
Canberra:
Australian national university,
1972.
Artikel.