NTT DATA at TREC-7: System Approach for Ad-Hoc and Filtering. - Hiroyuke Nakajima; Toru Takaki; Tsutomu Hirao; Akira Kitauchi (TREC, 1998)

Invalidity Patent Search System of NTT DATA. - Kazuya Konishi; Akira Kitauchi; Toru Takaki (NTCIR, 2004)