E. Bacchiocchi, M. Florio, and M. Gambaro. Telecommunications Policy, 35 (4):
382 - 396(2011)First published online: March 29, 2011, http://dx.doi.org/10.1016/j.telpol.2011.03.001. (Eurobarometer).
L. Toma, A. Stott, C. Revoredo-Giha, and B. Kupiec-Teahan. Appetite, 58 (2):
597-607(2012)First published online: November 19, 2011, http://dx.doi.org/10.1016/j.appet.2011.11.015. (Eurobarometer).