Norwich, John Julius, editor
Oxford University Press, 1990
Buku Referensi
edited by Dennis Sharp
Quarto Publishing, 1991
Buku Referensi
Larousse , 1972
Buku Referensi
Shealy, C. Norman
Element, 1998
Buku Referensi
Harris, Cyril M.
W.W. Norton, 1998
Buku Referensi