Examines how online versions of databases vary on different systems. Differences are grouped into three categories: obvious differences, including easily available information such as updating, dates covered, and price; database choice, including subfile structure, field structure, and content; and system choice, including support and system…

The effectiveness of using the age of references to control the exhaustivity of the reference representation in information retrieval was investigated through analysis of optimal cluster-based retrieval results. The results show that the foreground representation at its optimal level of exhaustivity is restricted to references with ages less than…