He is an expert in the issue of late-medieval European banking. Among his published articles are The Politics of Usury in Trecento Florence: The Questio de monte of Francesco da Empoli. (Mediaeval Studies 61 (1999)) and Usury, Conscience and Public Debt: Angelo Corbinelli's Testament of 1419. in A Renaissance of Conflicts: Visions and Revisions of Law and Society in Italy and Spain, an anthology edited by John A. Marino and Thomas Kuehn.