edited by Robert N. Singer, Milledge Murphey and L. Keith Tennat
Macmillan, 1993
Buku Referensi
Jarvis, Matt, 1966-
Routledge, 2005
Buku Teks
Cox, Richard H.
McGraw-Hill, 2007
Buku Teks
Coakley, Jay
McGraw-Hill, 2001
Buku Teks
Cox, Richard H.
McGraw-Hill, 2012
Buku Teks