Sallah, David, author
Elsevier , 2005
Buku Teks
Connors, Michael M., author
Pennsylvania International Textbook, 1967
Buku Teks
Babbie, Earl, author
Wadsworth, 2010
Buku Teks
Dunn, Dana S., author
Wiley-Blackwell, 2009
Buku Teks
Healey, Joseph F., 1945-, author
Cengage Learning, 2015
Buku Teks