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.
Wilfred J. Hansen. Progressive Acyclic Digraphs - A Tool for Database Integrity. Communications of the ACM, 22(9):513-518, 1979.
Abstract is missing.