## Description

The userdef element is an all-purpose element to store information not covered by the other elements. For reasons of consistency, a reference database administrator should figure out rules which kind of information should be stored in the userdef element.

The type element can be set to one of "1", "2", "3", "4", or "5", thus allowing to use 5 different userdef elements per dataset.

## Example

    <pubinfo>
    <pubdate type="primary">
    <date>
    <year>1999</year>
    </date>
    </pubdate>
    <city>Sebastopol</city>
    <publisher>O'Reilly</publisher>
    <serial>1-56592-580-7</serial>
    <address>millera@dinosaurs.upenn.edu</address>
    <link type="url">http://www.dinosaurs.upenn.edu/</url>
    <userdef type="1">high</userdef>
    </pubinfo>