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 (Walter De Gruyter, 1989)
Tekst referata na engl. i na njem. jeziku