1. Allport, G. W. (1954/1979). The nature of prejudice. Cambridge, MA: Perseus Books.;
2. Bernays, E., (1961). Crystallizing Public Opinion. New York: Liveright Publishing Corporation.;
3. Brande, T., (1842). Dictionary of Science, Literature an Art. Quoted in Smith, P., (1969). International propaganda. University of Minnesota.;
4. Cooley, C., (1922). Human Nature and The Social Order. Charles Scribner’s Sons.;
5. Curtis, M., (1998). Introduction. In Lippmann, W., Public Opinion. New Jersey: Rutgers-The State University New Brunswick.;