Minsk, Are you asking for the source code of these functions or for an example of use? The source code for the accumulate functions we ship with drools is here: http://anonsvn.labs.jboss.com/labs/jbossrules/trunk/drools-core/src/main/... Including source codes for min and max functions. The usage is similar to the others showed in the docs. Maybe we need to improve docs: Number( $max : intValue ) from accumulate( Cheese( $price : price ), max( $price ) ) []s Edson 2007/10/8, Chong Minsk Goh < cmgoh1979(a)gmail.com&gt;: -- Edson Tirelli Software Engineer - JBoss Rules Core Developer Office: +55 11 3529-6000 Mobile: +55 11 9287-5646 JBoss, a division of Red Hat @ www.jboss.com