M. Andersson, J. Glass, and R. Simon. Social Indicators Research, 115 (3):
945-961(2014)First published online: January 19, 2013, http://dx.doi.org/10.1007/s11205-013-0244-8. (ISSP).
H. Bekhuis, M. Lubbers, and M. Verkuyten. International Journal of Public Opinion Research, 26 (4):
487-500(2014)First published online: December 18, 2013, http://dx.doi.org/10.1093/ijpor/edt037. (Eurobarometer) (EVS) (ISSP).