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.
John Grant, Timos K. Sellis. Extended database logic: Complex objects and deduction. Inf. Sci., 52(1):85-110, 1990. [doi]
Abstract is missing.