Dietmar Berwanger Krishnendu Chatterjee Martin De Wulf Laurent Doyen Thomas A. Henzinger Alpaga: A Tool for Solving Parity Games with Imperfect Information. 58-61 2009 TACAS http://dx.doi.org/10.1007/978-3-642-00768-2_7 conf/tacas/2009 db/conf/tacas/tacas2009.html#BerwangerCWDH09