5Armbrust M, Fox A, Grith R, et al. Above the clouds: A Berkeley View of Cloud Computing [R].UCB/EECS- 2009-28.Berkeley,USA:Electrical Engineering and Com- puter Sciences, University of California at Berkeley,2009.
6Vaquero L, Rodero-Marino L, Caceres J, et al. A break in the clouds :towards a cloud definition [J].SIGCOMM Computer Communication Review,2009,39(1):50-55.
