Shoudong Huang Zhan Wang Gamini Dissanayake Sparse Local Submap Joining Filter for Building Large-Scale Maps. 1121-1130 2008 24 IEEE Transactions on Robotics 5 http://dx.doi.org/10.1109/TRO.2008.2003259 db/journals/trob/trob24.html#HuangWD08