Bob Gordon, consultant editor; Maggie Gordon, consultant editor
Watson-Guptill Publications, 2002
Buku Teks
Gomez-Palacio, Bryony, author
Page one publishing pte ltd, 2009
Buku Referensi
Greenburg, Steve, author
Alpha, 2002
Buku Referensi
Buchsbaum, Walter H., author
Prentice-Hall, 1977
Buku Teks
Knackstedt, Mary V., author
Wiley, 2005
Buku Referensi