Neil Burgess Tom Hartley Orientational and Geometric Determinants of Place and Head-direction. 165-172 2001 conf/nips/2001 NIPS http://www-2.cs.cmu.edu/Groups/NIPS/NIPS2001/papers/psgz/NS13.ps.gz db/conf/nips/nips2001.html#BurgessH01