Bryson, Bill, author
Penguin Books, 1987
Buku Referensi
Uvarov, E.B., author
Penguin, 1978
Buku Referensi
edited by D.W.A. Sharp
Penguin Books, 1983
Buku Referensi
Maclean, James H., author
Penguin Books, 1993
Buku Referensi
Whitten, D.G.A., 1921-, author
Penguin Books, 1972
Buku Referensi