Implementation of Inferential Relational Database System. - Toshihisa Takagi; Fumihiro Matsuo; Shouichi Futamura; Kazuo Ushijima (FODO, 1985)

Efficient Storage and Retrieval of Very Large Document Databases. - Fumihiro Matsuo; Shouichi Futamura; Takeshi Shinohara (ICDE, 1986)

A Hypermedia Document System Based on Relational Database. - Shouichi Futamura; Yoneharu Fujita; Kouichi Utsumiya (Future Databases, 1992)