Why did the talks of the Doha development round collapse?


Reasons I have researched so far:
-Agriculture at the main reason
-US and Europe acusing each other
-Lack of political willingsness

Are their any other good reasons?
Where to and how to find more results in an efficient way?

India and Brazil were very adamant on the elimination of tade
subsidies by both the USA and the EU. Just a bit of detail on your
first reason. Also, the USA is getting frustrated because the special
power handed to President Bush by Congress to allow any easy or easier
passage of any agreement reached by the Doha round of talks, expires
soon and after that, it could get very hard to get anything passed.