Hierarchical Concept Structures Based Data Retrieval/Mining by Fuzzy Document Ordering System. - Tadashi Ohashi; Hajime Nobuhara; Kaoru Hirota (J. Adv. Comput. Intell. Intell. Informatics, 2004)

A Semantic Concept Operation Based on Fuzzy Document Ordering System and its Application to Reuter Database. - Tadashi Ohashi; Hajime Nobuhara; Kaoru Hirota (J. Adv. Comput. Intell. Intell. Informatics, 2007)