Adamson, Paul
Gibss Smith, 2002
Buku Teks
Freeman, Joseph
Victor Gollancz, 1938
Buku Teks
Lacey, Nicola, author
Oxford University Press, 2006
Buku Teks
Bass, Herbert J.
Silver Burdett Co, 1979
Buku Teks
Powell, Colin L., author
Angkasa, 2001
Buku Teks