question: What year did the book by Brigo , Pallavicini and Torresetti report warnings and research on CDOs ?
answer: 2006
turker_answer: In 2006 the book by Brigo , Pallavicini and Torresetti reported warnings and research on CDOs .
rule-based: 2006 did the book by Brigo , Pallavicini and Torresetti report warnings and research on CDOs .