Sharp, Mick, author
Blandford, 1997
Buku Referensi
Sharp, Mick
London Blandford 1997,
Buku Referensi
Genzmer, Herbert, author
Parragon, 2010
Buku Referensi
Porter, Rev
T. Nelson and Sons, Paternoster Row, 1891
Buku Teks
Cowan, James, author
Simon & Schuster, 1991
Buku Teks