D. Brady, S. Marquardt, G. Gauchat, и M. Reynolds. Journal of Health Politics Policy and Law, 41 (3):
355-392(2016)First published online: February 26, 2016, http://dx.doi.org/10.1215/03616878-3523946. (ISSP).
M. Quaranta, и S. Martini. Electoral Studies, (2016)First published online: February 27, 2016, http://dx.doi.org/10.1016/j.electstud.2016.02.015. (Eurobarometer).