Li Zhang Zheng Pei Honghua Chen Extracting Fuzzy Linguistic Summaries Based on Including Degree Theory and FCA. 273-283 2007 conf/ifsa/2007 IFSA (1) http://dx.doi.org/10.1007/978-3-540-72950-1_28 db/conf/ifsa/ifsa2007.html#ZhangPC07