Herman, A. L., author
Westview Press, 1991
Buku Referensi
Riggio, Ronald E., author
Pearson, 2009
Buku Teks
Hergenhahn, B.R., 1934-, author
Wadsworth, 2009
Buku Teks
Nietzel, Michael T., author
Prentice-Hall, 1987
Buku Teks
Argyle, Michael, author
Routledge & Kegan Paul, 2000
Buku Teks