Can you recommend some sources that will help me gain an understanding of the contributing factors to the European Sovereign Debt crisis?

Hello Social Scientists,

I need to write a very short paper that outlines at least five contributing factors to the present European Sovereign Debt crisis. I'm scouring the internet, but I'm wondering if any of you know of any good articles or papers you would recommend. Since it's all pretty new, choosing reliable sources is a little bit of a challenge, and I'm not very familiar with the situation coming into this. So far I'm focusing on the inception of the Eurozone itself and subsequent loss of monetary policy of Eurozone countries (Greece, obviously, primarily), and the practice of obscuring Greece's debt levels using complex financial instruments provided, apparently primarily, by Goldman Sachs (is there a financial crisis that they are not at the center of?). Any other suggestions?

Thanks!