Omparison of credibility (accuracy) of S&P and Moodys ratings before and after the US financial crisis

Helllo… This is actually part of a literature review that I have already started on… Ie I do not need any introductory sentences just directly on the following please:
250 wordsS&P and Moodys rating influence on the US financial market
1000 wordsLiterature review on the methodology changes of S&P and Moodys after all the criticism it has faced on their in credibility and accuracy of their published ratings… They have become more cautious etc…

Referencing Requirements:
Book 1 (Credit risk management in and out of the financial crises)
Book 2 (Credit, currency, or derivatives: instruments of global financial stability or crises)
Book 3 (Global finance in crises: the politics of international regulatory change)
Book 4 (The rating agencies and their credit ratings What they are, How they work, and why they are relevant)