Artikel Jurnal
Moyar, Mark, author
Cambridge University Press, 2006
Buku Teks
Windchy, Eugene G.
Doubleday & Co., 1971
Buku Teks
Palmer, E.H., author
Routledge & Kegan Paul, 1956
Buku Referensi
Boyle, John Andrew, author
Luzac & Company, 1949
Buku Referensi