Penchef, Esther
Caufield Press, 1971
Buku Teks SO
McCormack, T.H.
University Tutonial Press, 1980
Buku Teks SO
Lavrenyov, Boris
Foreign Languages Publishing, [date of publication not identified]
Buku Teks SO
Hamblin, Dora Jane
Time-Life International, 1975
Buku Teks SO
Covey, Stephen R.
Gramedia Pustaka Utama, 1995
Buku Teks