Twisk, Jos W.R., author
Cambridge University Press, 2006
Buku Teks
Hand, D.J., author
Chapman & Hall, 1987
Buku Teks
Jones, Andrew, author
Radcliffe Publishing, 2009
Buku Teks
Johnson, Richard A., author
Pearson Education International, 2007
Buku Teks
Morrison, Donald F., author
Prentice-Hall, 1983
Buku Teks