Zhao Zhang Weili Wu Shashi Shekhar Optimal placements of replicas in a ring network with majority voting protocol. 461-469 2009 69 J. Parallel Distrib. Comput. 5 http://dx.doi.org/10.1016/j.jpdc.2009.02.007 db/journals/jpdc/jpdc69.html#ZhangWS09