[Stoop, I., J. Billiet, A. Koch, and R. Fitzgerald. 2010. Improving Survey Response: Lessons Learned from the European Social Survey. Chichester, UK: Wiley.10.1002/9780470688335]Search in Google Scholar
[Tourangeau, R. and T. Yan. 2007. “Sensitive Questions in Surveys.” Psychological Bulletin 133: 859-883. Doi: http://dx.doi.org/10.1037/0033-2909.133.5.859.10.1037/0033-2909.133.5.859]Search in Google Scholar
