Pease, Martha Redding, author
Fourth Estate, 1984
Buku Referensi
McColvin, Eric, author
Longmans, Green and Co., 1946
Buku Teks
London : Chatto & Windus
Majalah, Jurnal, Buletin
Ilana Tan, author
Gramedia Pustaka Utama, 2010
Buku Teks
London His Majesty's Stationery Office 1935
Buku Teks