Bickham, George
P. A. Struck, 1941
Buku Referensi
Hankes, Elmer Joseph
Hankes Foundation, 1992
Buku Teks SO
Wechler, Wolfgang
Springer-Verlag , 1992
Buku Teks
Kaelany H.D.
Midada Rahma Press, 2006
Buku Teks
Arthur, Paul, 1924-
Focus Strategic Communications, 2005
Buku Teks