1. Avendabo, M., Mackenbach, J. P., & Scherpenzeel, A. (2010). Can biomarkers be collected in an internet survey? A pilot study in the LISS panel. In M. Das, P. Ester & L. Kaczmirek (Eds.), Social and behavioral research and the internet: Advances in applied methods and research strategies. Routledge: Taylor and Francis Group.
2. De Leeuw Edith, E. D. (2005). To mix or not to mix data collection modes in surveys. Journal of Official Statistics,
21(2), 233–255.
3. Eurostat. (2009). Harmonised European time use surveys. 2008 Guidelines. Luxembourg: Publications Office of the European Union.
4. Eurostat. (2011). Quality report of the European Union Labour Force Survey 2009. Luxembourg: Publications Office of the European Union.
5. Groves, R. M. (1989). Survey errors and survey costs. New York: Wiley.