@Article{kotla09zyzzyva, 
author = {R. Kotla and L. Alvisi M. Dahlin and A. Clement and E. Wong}, 
 title = {Zyzzyva: Speculative Byzantine fault tolerance}, 
 journal = {ACM Transactions on Computer Systems}, 
 year = 2009 , 
 volume = 27 , 
 number = 4 , 
 month = Dec, 
 category = "byz", 
 pdf = "http://doi.acm.org/10.1145/1658357.1658358" 
 }