Rainer Kümmerle Rudolph Triebel Patrick Pfaff Wolfram Burgard Monte Carlo localization in outdoor terrains using multilevel surface maps. 346-359 2008 25 J. Field Robotics 6-7 http://dx.doi.org/10.1002/rob.20245 db/journals/jfr/jfr25.html#KummerleTPB08