There a book about him (On Being a Christian in the Academy: Nicholas Wolterstorff and the Practice of Christian Scholarship) but very little by him. Please get some or all of these:
- Nicholas Wolterstorff. Reason within the Bounds of Religion (Eerdmans, 1988)
- Nicholas Wolterstorff. Art in Action: Toward a Christian Aesthetic (Eerdmans, 1987)
- Nicholas Wolterstorff. Hearing the Call: Liturgy, Justice, Church, and World (Eerdmans, 2011)
- Nicholas Wolterstorff. Justice in Love (Eerdmans, 2011)
- Nicholas Wolterstorff. Until Justice and Peace Embrace (Eerdmans, 1983)
- Nicholas Wolterstorff. Educating for Shalom: Essays on Christian Higher Education (Eerdmans, 2004)
- Nicholas Wolterstorff. Educating for Life: Reflections on Christian Teaching and Learning (Baker Academic, 2002)
- Nicholas Wolterstorff. Justice: Rights and Wrongs (Princeton University Press, 2007)
- Nicholas Wolterstorff. Divine Discourse: Philosophical Reflections on the Claim that God Speaks (Cambridge University Press, 1995)
- Nicholas Wolterstorff. The Mighty and the Almighty: An Essay in Political Theology (Cambridge University Press, 2014)
- Nicholas Wolterstorff. Inquiring about God: Volume 1, Selected Essays (Cambridge University Press, 2014)
- Nicholas Wolterstorff. Practices of Belief: Volume 2, Selected Essays (Cambridge University Press, 2014)
- Jurgen Moltmann, Nicholas Wolterstorff and Ellen T. Charry. A Passion for God's Reign (Eerdmans, 1998)
- Alvin Plantinga and Nicholas Wolterstorff, eds. Faith And Rationality: Reason and Belief in God (University of Notre Dame Press, 1991)
- Robert Audi and Nicholas Wolterstorff. Religion in the Public Square: The Place of Religious Convictions in Political Debate (Point/Counterpoint: Philosophers Debate Contemporary Issues) (Rowman & Littlefield, 1996)
He's more generally Evangelical than specifically Reformed, but he did teach at Calvin College, and I find that posting suggestions to a specific denominational forum gets more definite attention.