Researchr is a web site for finding, collecting, sharing, and reviewing scientific publications, for researchers by researchers.
Sign up for an account to create a profile with publication list, tag and review your related work, and share bibliographies with your co-authors.
Peter Päppinghaus. T und Definierbarkeit von Ordinalzahlen. Arch. Math. Log., 28(2):119-141, 1989. [doi]