Martin Braschler Carol Peters CLEF 2003 Methodology and Metrics. 7-20 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3237&spage=7 2003 conf/clef/2003 CLEF db/conf/clef/clef2003.html#BraschlerP03