Ashley W. Stroupe Kevin Sikorski Tucker R. Balch Constraint-Based Landmark Localization. 8-24 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2752&spage=8 2002 conf/robocup/2002 RoboCup db/conf/robocup/robocup2002.html#StroupeSB02