Rutherford, Donald, author
Routledge, 1992
Buku Referensi
Blackwell, 1999
Buku Teks
Bannock, G., author
Penguin Books, 1974
Buku Referensi
Rutherford, Donald, author
Routledge, 1995
Buku Referensi
Bannock, G., author
Allen Lane / The Viking Press, 1979
Buku Referensi