Sabine Gillner Hanspeter A. Mallot These Maps Are Made for Walking - Task Hierarchy of Spatial Cognition. 181-201 2008 Robotics and Cognitive Approaches to Spatial Mapping http://dx.doi.org/10.1007/978-3-540-75388-9_11 series/star/2008-38 db/series/star/star38.html#GillnerM08