T. Sun. International Journal of Consumer Studies, 35 (3):
330--337(2011)First published online: October 12, 2010, http://dx.doi.org/10.1111/j.1470-6431.2010.00938.x. (Eurobarometer).
A. Khan, N. Li, X. Yan, Z. Guan, S. Chakraborty, and S. Tao. Conference, International Conference on Management of Data (SIGMOD/PODS 2011), Athens, Greece - June 12 - 16, 2011, page 901--912. New York, NY, USA, ACM, (2011)