edited by D. Henry Edel
Prentice-Hall, 1967
Buku Teks
Gawain, Shakti, author
Whatever Publisher, 2002
Buku Teks
Krum, Randy, author
John Wiley & Sons, 2014
Buku Teks
Knaflic, Cole Nussbaumer, author
John Wiley & Sons, 2015
Buku Teks
Ursyn, Anna, 1955-, author
Igi Global, 2014
Buku Teks