Yonit Kesten Amir Pnueli Complete Proof System for QPTL. 701-745 2002 12 J. Log. Comput. 5 http://www3.oup.co.uk/logcom/hdb/Volume_12/Issue_05/120701.sgm.abs.html db/journals/logcom/logcom12.html#KestenP02