[Q]: Sentence: Krugman's contention (that the growth of a commercial real estate bubble indicates that U.S. housing policy was not the cause of the crisis) is challenged by additional analysis. Question: When did Xudong An and Anthony B. Sanders issue a report about commercial mortgage-backed securities?
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[A]: no

[Q]: Sentence: They cover much of the floor of a finely decorated building that probably served as the palace of a local governor. Question: Where can the most superb example of Umayyad mosaic floor paneling?
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[A]: no

[Q]: Sentence: A definition of pain widely employed in nursing, emphasizing its subjective nature and the importance of believing patient reports, was introduced by Margo McCaffery in 1968: "Pain is whatever the experiencing person says it is, existing whenever he says it does". Question: What did Margo McCaffery introduce in 1968?
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[A]:
yes