Reason for suggesting change: (If suggesting a new term, please mention the sense or context in which the term occurs if you cannot define it.)
Citations: (One or more authoritative citations, either from MEDLINE or other sources, are requested, particularly if the concept or term is quite new or rarely written about.)
Last reviewed: 15 February 2008Last updated: 20 November 2001First published: 20 November 2001Metadata| Permanence level: Permanence Not Guaranteed