Gaya APA
rangkuti, S., Hasibuan, . (1993).
English for specific purposes : Tourism Hotel a Major in the academy of tourism .
Jakarta:
Dian Rakyat.
Gaya MLA
rangkuti, Sofia., Hasibuan, .
"English for specific purposes : Tourism Hotel a Major in the academy of tourism".
Jakarta:
Dian Rakyat,
1993.
BUKU.