Xiaohua Zhou Xiaohua Hu Guangren Li Xia Lin Xiaodan Zhang Relation-Based Document Retrieval for Biomedical IR. 112-128 2006 journals/tcsb/2006-5 T. Comp. Sys. Biology http://dx.doi.org/10.1007/11790105_9 db/journals/tcsb/tcsb5.html#ZhouHLLZ06