Ittai Balaban Amir Pnueli Lenore D. Zuck Invisible Safety of Distributed Protocols. 528-539 2006 conf/icalp/2006-2 ICALP (2) http://dx.doi.org/10.1007/11787006_45 db/conf/icalp/icalp2006-2.html#BalabanPZ06