Rybak, Stephanie
Macmillan, 1985
Buku Teks
Barratt, William B.
Aldine House, 1994
Buku Teks
Whitmarsh, W.F.H.
Longmans, Green, 1960
Buku Teks
Skaife, Linda
National Textbook Company, 1994
Buku Teks
Bladon, Rachel
Passport Books, [Date of publication not identified]
Buku Teks