D`Anieri, Paul, author
Wadsworth and Cengage Learning, 2012
Buku Teks
Blackburn, Glenn, author
St. Martin's, 1985
Buku Teks
Rourke, John T., author
McGraw-Hill, 2001
Buku Teks
Kegley, Charles William, Jr., author
St. Martin`s Press, 1997
Buku Teks
Rourke, John T., author
McGraw-Hill, 2010
Buku Teks