Wann, David, author
Island Press, 1996
Buku Teks
Eisenmann, Thomas R., author
McGraw-Hill Irwin, 2002
Buku Teks
Jones, Graham, author
Glorier International, 2001
Buku Referensi
by Arnold de Meyer ... [and others]
John Wiley & Sons, 2005
Buku Teks
Bagley, Edward R., author
Amacom, 1975
Buku Teks