Gaya APA
Hasibuan, S, R. (1990).
English for specific purposes agriculture/ Sofia Rangkuti Hasibuan .
Jakarta:
Gramedia Pustaka Utama.
Gaya MLA
Hasibuan, Sofia, Rangkuti.
"English for specific purposes agriculture/ Sofia Rangkuti Hasibuan".
Jakarta:
Gramedia Pustaka Utama,
1990.
Text.