editedby Robert N. Singer, Heather A. Hausenblas and Christopher M. Janelle
Wiley, 2001
Buku Teks
edited by Robert N. Singer, Milledge Murphey and L. Keith Tennat
Macmillan, 1993
Buku Referensi
Jarvis, Matt, 1966-, author
Routledge, 2005
Buku Teks
Cox, Richard H., author
McGraw-Hill, 2007
Buku Teks
Coakley, Jay, author
McGraw-Hill, 2001
Buku Teks