Wilhelm Friedrich Hegel, Thomas Aquinas, and John Locke. Wikipedia's articles were compared to a consensus list of themes culled from four reference works in philosophy. Bragues found that, on average, Wikipedia's articles only covered 52% of consensus themes. No errors were found, though there were significant omissions. PC Pro magazine (August 2007) asked experts to compare four articles (a small sample) in their scientific fields between Wikipedia, Britannica and Encarta. In each case Wikipedia was described as "largely sound", "well handled", "performs well", "good for the bare facts" and "broadly accurate". One article had "a marked deterioration towards the end" while another had "clearer and more elegant" writing, a third was assessed as less well written but better detailed than its competitors, and a fourth was "of more benefit to the serious student than its Encarta or Britannica equivalents". No serious errors were noted in Wikipedia articles, whereas serious errors were noted in one Encarta and one Britannica article. In October 2007, the Australian magazine PC Authority published a feature article on the accuracy of Wikipedia. The article compared Wikipedia's content to other popular online encyclopedias, namely Britannica and Encarta. The magazine asked experts to evaluate articles pertaining to their field. A total of four articles were reviewed by three experts. Wikipedia was comparable to the other encyclopedias, topping the chemistry category. In December 2007, German magazine Stern published the results of a comparison between the German Wikipedia and the online version of the 15-volume edition of Brockhaus Enzyklopädie. The test was commissioned to a research institute (Cologne-based WIND GmbH), whose analysts assessed 50 articles from each encyclopedia (covering politics, business, sports, science, culture, entertainment, geography, medicine, history and religion) on four criteria (accuracy, completeness, timeliness and clarity), and judged Wikipedia articles to be more accurate on the average (1.6 on a scale from 1 to 6 versus 2.3 for Brockhaus, with 1 as the best and 6 as the worst). Wikipedia's coverage was also found to be more complete and up to date; however, Brockhaus was judged to be more clearly written, while several Wikipedia articles were criticized as being too complicated for non-experts, and many as too lengthy. In its April 2008 issue British computing magazine PC Plus compared the English Wikipedia with the DVD editions of World Book Encyclopedia and Encyclopædia Britannica, assessing for each the coverage of a series of random subjects. It concluded, "The quality