Hans P. van Ditmarsch Andreas Herzig Tiago De Lima Optimal Regression for Reasoning about Knowledge and Actions. 2007 Formal Models of Belief Change in Rational Agents http://drops.dagstuhl.de/opus/volltexte/2007/1207 conf/dagstuhl/2007P7351 db/conf/dagstuhl/P7351.html#DitmarschHL07