Two plagiarized articles on Thomas Aquinas have been retracted in recent weeks: 

• M.W.F. Stone, “Practical Reason and the Orders of Morals and Nature in Aquinas’s Theory of the Lex Naturae”, in Mind, Metaphysics, and Value in the Thomistic and Analytical Traditions, ed. John Haldane (Notre Dame, IN: University of Notre Dame Press, 2002), pp. 195-212 
• M.W.F. Stone, “The Angelic Doctor and the Stagirite: Thomas Aquinas and Contemporary ‘Aristotelian’ Ethics”, in Proceedings of the Aristotelian Society 101 (2001), pp. 97-128 

Regarding the first article, University Notre Dame Press has appended a note to the book’s online advertisement that states: 

Parts […] have been subject to claims of plagiarism. The editor and publisher as a result cannot stand behind the noted material as originally contained in this volume.

Regarding the second, Wiley-Blackwell Publishing has published a short article titled “Retraction” in the most recent issue of the journal that states in part: 

The retraction has been agreed due to significant overlap with previously published material. 

Details of the plagiarism for these and additional cases were set forth in “40 Cases of Plagiarism” in Bulletin de Philosophie Médiévale 51/2009 (Turnhout: Brepols, 2010), pp. 350-391, compiled by Pernille Harsting, Russell L. Friedman, and me. For an earlier discussion, see here.