Gaya APA
Mellgren, ., Walker, . (1973).
Workbook New Horizon in English 1 .
United States of America:
Addison-Wesley Publishing Company.
Gaya MLA
Mellgren, ., Walker, .
"Workbook New Horizon in English 1".
United States of America:
Addison-Wesley Publishing Company,
1973.
Teksbook.