Michael Magee William Hoff Lance Gatrell Martin Marietta William J. Wolfe Integrated Planning of Robotic and Computer Bision Based Spatial Reasoning Tasks. 196-206 1990 IEA/AIE (Vol. 1) http://doi.acm.org/10.1145/98784.98820 db/conf/ieaaie/ieaaie1990-1.html#MageeHGMW90