Added Thrun's paper on robotic mapping.

This paper is a comprehensive introduction to mapping.

README.md

@@ -68,6 +68,8 @@ Simultaneous Localization and Mapping, also known as SLAM, is the computational
 - [Lagrangian duality in 3D SLAM: Verification techniques and optimal solutions](http://arxiv.org/abs/1506.00746) (2015)
 - [A Solution to the Simultaneous Localization and Map Building (SLAM) Problem](http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=938381&tag=1)
 - [Simulataneous Localization and Mapping with the Extended Kalman Filter](http://www.iri.upc.edu/people/jsola/JoanSola/objectes/curs_SLAM/SLAM2D/SLAM%20course.pdf)
+- [Robotic Mapping: A Survey](http://robots.stanford.edu/papers/thrun.mapping-tr.pdf)
+
 
 ### Researchers