@techreport{weko_34011_1,
   author	 = "GeorgeSerbanRadescu and Satoshi,Ogawa and Wenpeng,Wei and Gen,Kitagata and Atsushi,Takeda and Norio,Shiratori",
   title	 = "A Flexible Model of Access Control based on Social Relations ",
   year 	 = "2008",
   institution	 = "Research Institute of Electrical Communication  Graduate School of Information Science  Tohoku University, Research Institute of Electrical Communication  Graduate School of Information Science  Tohoku University, Research Institute of Electrical Communic",
   number	 = "54(2008-DPS-135)",
   month	 = "jun"
}