Campbell, Byram, author
The Truth Seeker, 1958
Buku Teks
Solomos, John, author
Routledge, 1995
Buku Teks
Knowles, Caroline, author
Sage, 2003
Buku Teks
Henslin, James M., author
McGraw-Hill, 1983
Buku Teks
Etzioni, Amitai, author
Prentice-Hall, 1976
Buku Teks