@techreport{weko_203885_1,
   author	 = "Masato,Kikuchi and Takao,Okubo",
   title	 = "Consideration of Extreme Risks in Cyberspace using Systems Thinking",
   year 	 = "2020",
   institution	 = "Institute of Information Security, Institute of Information Security",
   number	 = "3",
   month	 = "mar"
}