Scurfield, Elizabeth, author
NTC Pub. Group, 1992
Buku Teks
Schafer, Edward H., author
Time-Life International, 1968
Buku Teks
Hodous, Lewis
Arthur Probstain, 1929
Buku Teks
Pustaka Bahasa Asing, 1995
Buku Referensi
Speiser, Werner, author
Methuen , 1960
Buku Teks