Use of different search engines to construct the FVs and assess the quality of the FVs. In (Tomassen
& Strasunskas, 2010) we found that change of comparable search engines does not yield any major
effect on the FV quality if an adequate number of search results is used. In this paper, the top 100
retrieved documents were used to construct the FVs, which are considered as a sufficient amount of
search results.