Steve Smith has compiled some helpful data regarding the citations of the Old Testament in the New Testament. This is a difficult issue, and Stephen's chart helps one to see some of the broad patterns of source citation.
For those interested in exploring this issue in more depth, I'd highly recommend Greg Beale's article, "Did Jesus and His Followers Preach the Right Doctrine From the Wrong Texts? An Examination of the Presuppositions of the Apostles' Exegetical Method," Themelios 14 (1989), 89-96; reprinted in The Right Doctrine From the Wrong Texts? Essays on the Use of the Old Testament in the New Testament, ed. G. K. Beale (Grand Rapids: Baker, 1994), 387-404.