Gaya APA
Mellgren, ., Walker, . (1975).
Workbook New Horizon in English 6 .
United States of America:
Addison-Wesley Publishing Company.
Gaya MLA
Mellgren, ., Walker, .
"Workbook New Horizon in English 6".
United States of America:
Addison-Wesley Publishing Company,
1975.
Teksbook.