PS

PhD Thesis, Department of Computer Sciences, The University of Texas at Austin.

@PhdThesis{wanyiklee:phd96, title={Spatial Semantic Hierarchy for a Physical Mobile Robot}, author={Wan Yik Lee}, school={Department of Computer Sciences, The University of Texas at Austin}, address={Austin, TX}, url="http://www.cs.utexas.edu/users/ai-lab?wanyiklee:phd96", year={1996} }