Freyermuth, R. Wilson, author
Thomson/West, 2011
Buku Teks
McJohn, Stephen M., 1959-, author
Wolters Kluwers, 2015
Buku Teks
Smith, Roger J., author
Longman, 2000
Buku Teks
Eastaway, Nigel, author
Sweet & Maxwell, 2008
Buku Teks
Matthew David, Debora Halbert, editors
SAGE Publications, 2015
Buku Teks