Erik Baldwin is a graduate student at Purdue. He's also a visiting graduate student at Notre Dame, doing research at their Center for Philosophy of Religion. In his paper "Could the Extended Aquinas/Calvin Model Defeat Basic Christian Belief?", (Philosophia Christi 8:2 (2006), pp. 383-399), he raises concerns about Plantinga's model of warranted Christian belief. In the process, he does an excellent job of clarifying Plantinga's account.
P.S., Recall that Erik Baldwin is the one who co-authored this nice paper with Michael Thune (one of his former fellow grad students at Purdue).