White, Charles
Haynes Publishing, 1992
Buku Referensi
Porter, Lindsay
Haynes Publishing, 1991
Buku Referensi
Michael G. Grantham, editor
Routledge, 2011
Buku Teks
Escoe, A. Keith
Elsevier, 2008
Buku Teks
Farnell, Warren M.
Pearson-Prentice Hall, 2006
Buku Teks