1. B. Noble, D. Clark, M. Meldrum, H. Ten Have, J. Seymour, M. Winslow and S. Paz, ‘The Measurement of Pain, 1945–2000’, Journal of Pain and Symptom Management, 29(1) (2005): 14–21.
2. Lonaine J. Daston and Peter L. Galison, Objectivity (New York: Zone Books, 2007).
3. Gail A. Hornstein, ‘Quantifying Psychological Phenomena: Debates, Dilemmas, and Implications’, in J.G. Morawski (ed.), The Rise of Experimentation in American Psychology (New Haven: Yale University Press, 1988), 1–34.
4. Edwin G. Boring, Sensation and Perception in the History of Psychology (New York: Appleton-Century Company, 1942), 467.
5. Roselyne Rey The History of Pain (Cambridge, MA: Harvard University Press, 1998), 215–16.