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.
Martin Kühnrich. Superclasses in a Finite Extension of Zermelo Set Theory. Math. Log. Q., 24(31-36):539-552, 1978. [doi]
Abstract is missing.