Hall, James, author
John murray, 1995
Buku Referensi
Harty, F. J., author
EGC, 1995
Buku Referensi
Hordeski, Michael F.
McGraw-Hill, 1995
Buku Referensi
Campbell, Alastair, author
Chronicle Books, 2000
Buku Referensi
The World Publishing Company, 1943
Buku Referensi