Xiaozhi Du Yong Qi Di Hou Ying Chen Xiao Zhong A Mixed Software Rejuvenation Policy for Multiple Degradations Software System. 376-383 2009 HPCC http://dx.doi.org/10.1109/HPCC.2009.18 conf/hpcc/2009 db/conf/hpcc/hpcc2009.html#DuQHCZ09