George Allen and Unwin, 1984
Buku Teks
Qureshi, Asif H. , author
Cambridge University Press, 2015
eBooks
Christou, Richard, author
Sweet & Maxwell, 2004
Buku Teks
United Nations, [date of publication not identified]
Buku Teks
Christou, Richard, author
Thomson Reuters, 2011
Buku Teks