Gilbert, Dorothy B.
R.R.Bowker, [date of publication not identified]
Buku Teks
Routledge, Taylor & Francis Group, 2007
Buku Referensi
Hazel, John
Routledge, 2000
Buku Teks
Hazel, John
Routledge, 2000
Buku Referensi
Europe Publications Limited, 1984
Buku Referensi