Beyfus, Drusilla
Reed International Books, [date of publication not identified]
Buku Teks
Mayeroff, Milton
Gramedia Pustaka Utama, 1993
Buku Teks
Simorangkir, O. P., author
Ind-Hill, 1985
Buku Teks
Simorangkir, O. P., author
Aksara Persada Indonesia , 1989
Buku Teks
Robinson, David
Gramedia Pustaka Utama, 1996
Buku Teks