Check these references:
Belloc, Hilaire. “On Usury.” Essays of a Catholic. Rockford, IL: Tan Books and Publishers, Inc., 1993, 15-28.
Brown, Raymond E., S.S., Joseph A. Fitzmeyer, S.J., and Roland E. Murphy, O.Carm., eds. The New Jerome Biblical Commentary. Englewood Cliffs, NJ: Prentice-Hall, Inc., 1990.
De Solenni, Mario. “Usury: The Rise and Fall of a Moral Idea.” Triumph (December 1971): 24-27.
___ “Interest.” In New Catholic Encyclopedia, vol. 7. Washington D.C.: The Catholic University of America, 1967; New York: McGraw-Hill Book Co., 568-569.
___ “Usury.” In New Catholic Encyclopedia, vol. 14. Washington D.C.: The Catholic University of America, 1967; New York: McGraw-Hill Book Co., 498-500.
From the bibliography of a paper by:
Father Gary L Coulter, Mount Saint Mary’s Seminary, Emmitsburg, Maryland, “The Church and Usury: Error, Change or Development?” A Research Paper Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Arts in Theology, Submitted August 15, 1999.
Someone provided a link to it with in the past two weeks on the forums. Try a search on Usury. It provided some decent information, but I didn’t save the link. Sorry.