Whatley, M., Webster, J., Smith, R., & Rhodes, A. (1999). The effect of a favor on public and private compliance: How internalized is the norm of reciprocity?. Basic and Applied Social Psychology, 21(3), 251-259. doi:10.1207/S15324834BASP2103_8.

Jonas, E., Martens, A., Niesta Kayser, D., Fritsche, I., Sullivan, D., & Greenberg, J. (2008). Focus theory of normative conduct and terror management theory: the interactive impact of mortality salience and norm salience on social judgment. Journal of Personality and Social Psychology, 95(6) 12391251.