Giorgio Grisetti Cyrill Stachniss Wolfram Burgard Improved Techniques for Grid Mapping With Rao-Blackwellized Particle Filters. 34-46 2007 23 IEEE Transactions on Robotics 1 http://dx.doi.org/10.1109/TRO.2006.889486 db/journals/trob/trob23.html#GrisettiSB07