Bormann, Ernest G.
Erlangga, 1991
Buku Teks SO
Hybels, Saundra
D. Van Nostrand, 1974
Buku Teks SO
O`Shaughnessy, Douglas, 1950-
Addison-Wesley, 1987
Buku Teks SO
Ellingsworth, Huber W.
Prentice-Hall, 1967
Buku Teks
Byrd, Dani
Wiley-Blackwell, 2010
Buku Teks SO