Suman Roy 0001 Guido Sciavicco Reasoning with 'And Then' and 'While'. 181-188 2007 conf/time/2007 TIME https://doi.org/10.1109/TIME.2007.57 https://doi.ieeecomputersociety.org/10.1109/TIME.2007.57 db/conf/time/time2007.html#RoyS07