God and being : the problem of ontology in the philosophical theology of Paul Tillich : contributions made to the II. International Paul Tillich Symposium held in Frankfurt 1988 = Gott und Sein : das Problem der Ontologie in der philosophischen Theologie Paul Tillichs : Beitraege des II. Internationalen Paul-Tillich-Symposions in Frankfurt 1988 - Hummel, Gert (Theologische Bibliothek Toepelmann ;, 1989)