Refinements of Complexity Results on Type Consistency for Object-Oriented Databases. - Yasunori Ishihara; Shougo Shimizu; Hiroyuki Seki; Minoru Ito (J. Comput. Syst. Sci., 2001)

Bag-based data models for incomplete information and their closure properties. - Akinari Yamaguchi; Shougo Shimizu; Yasunori Ishihara; Toru Fujiwara (J. Intell. Inf. Syst., 2008)

A Tractable Subclass of DTDs for XPath Satisfiability with Sibling Axes. - Yasunori Ishihara; Takuji Morimoto; Shougo Shimizu; Kenji Hashimoto; Toru Fujiwara (DBPL, 2009)

Extending the Tractability Results on XPath Satisfiability with Sibling Axes. - Yasunori Ishihara; Shougo Shimizu; Toru Fujiwara (XSym, 2010)

XPath satisfiability with downward and sibling axes is tractable under most of real-world DTDs. - Yasunori Ishihara; Kenji Hashimoto; Shougo Shimizu; Toru Fujiwara (WIDM, 2012)

XPath Satisfiability with Parent Axes or Qualifiers Is Tractable under Many of Real-World DTDs. - Yasunori Ishihara; Nobutaka Suzuki; Kenji Hashimoto; Shougo Shimizu; Toru Fujiwara (DBPL, 2013)