Adam J. Chlipala J. Gregory Malecha Greg Morrisett Avraham Shinnar Ryan Wisnesky Effective interactive proofs for higher-order imperative programs. 79-90 2009 ICFP http://doi.acm.org/10.1145/1596550.1596565 conf/icfp/2009 db/conf/icfp/icfp2009.html#ChlipalaMMSW09