Ulrich Schmid Bettina Weiss Idit Keidar Impossibility Results and Lower Bounds for Consensus under Link Failures. 1912-1951 2009 38 SIAM J. Comput. 5 http://dx.doi.org/10.1137/S009753970443999X db/journals/siamcomp/siamcomp38.html#SchmidWK09