Ryan Eustice Oscar Pizarro Hanumant Singh Visually Augmented Navigation in an Unstructured Environment using a Delayed State History. 25-32 2004 conf/icra/2004 ICRA http://dx.doi.org/10.1109/ROBOT.2004.1307124 db/conf/icra/icra2004-1.html#EusticePS04