McColvin, Eric
Longmans, Green and Co., 1946
Buku Teks
London : Chatto & Windus
Majalah, Jurnal, Buletin
Ilana Tan
Gramedia Pustaka Utama, 2010
Buku Teks
London His Majesty's Stationery Office 1935
Buku Teks
Longstaffe-Gowan, Todd
Yale University Press, 2001
Buku Teks