EN: The current issue of Nature contains a special report  and an editorial  reporting the good quality of scientific articles in Wikipedia. A comparison shows that on average the number of errors is not much higher than in Encyclopaedia Britannica.
The topic is also discussed in the current entry of Nature podcast.
 "Internet encyclopaedias go head to head", Nature, 438, 900-901, 15 December, 2005
 "Wiki's wild world - Researchers should read Wikipedia cautiously and amend it enthusiastically", Nature, 438, 890, 15 December, 2005