English Language Services; editor, Charles J. Hirsch, James A. Curtin
Collier/Macmillan, 1971
Buku Teks
English Language Services; editor, Charles J. Hirsch, James A. Curtin
Collier/Macmillan, 1970
Buku Teks
Rangkuti-Hasibuan, Sofia, author
Gramedia, 1986
Buku Teks
Harrison, G.B., author
Penguin Books , 1953
Buku Teks
McGraw-Hill, 1964
Buku Teks