Keping Zhao Shuigeng Zhou Aoying Zhou Towards Efficient Ranked Query Processing in Peer-to-Peer Networks. 145-160 2005 conf/cogsys/2005 Cognitive Systems http://dx.doi.org/10.1007/978-3-540-70934-3_13 db/conf/cogsys/cogsys2005.html#ZhaoZZ05