Some databases cite other sources of information in addition to journal articles, such as books, book chapters, conference proceedings, dissertations, government publications, etc.
The following example from the Environmental Sciences and Pollution Management database is a symposium paper. This is not evident in the brief database entry, which just gives the tile of the symposium paper, the author of the paper, the publisher, place of publication, and year.

The detailed database entry provides the complete information, including the name of the symposium and the page numbers.
