7Francesco, D' Amuri, Juri Marcucci, 2010, "'" Google it!" Fore- casting the US Unemployment Rate with a Google Job Search Index", Working Paper.
8Hulth A., Rydevik G., Linde A., 2009, Web Queries as a Source for Syndromic Surveillance,PLOS ONE,4(2),e4378.
9Nicolas Della Penna, Haifang Huang, 2009, "Constructing a Consumer Confidence Index for the US Using Web Search Volume" , Working Paper.
10Engle R. F., C. W. J. Granger, 1987, "Co-integration and Er- ror Correction: Representation, Estimation and Testing", Econometrica: Journal of the Econometric Society, pp.251-276.
