A Unified Approach to the Logical Design of a Hierarchical Data Model. - Hirotaka Sakai (ER, 1979)

Entity-Relationship Approach to the Conceptual Schema Design. - Hirotaka Sakai (SIGMOD Conference, 1980)

A Development of a Conceptual Schema Design Aid in the Entity-Relationship Model. - Hirotaka Sakai; Hidefumi Kondo; Zenshiro Kawasaki (ER, 1981)

A Method for Defining Information Structures and Transactions in Conceptual Schema Design - Hirotaka Sakai (VLDB, 1981)

A Method for Entity-Relationship Behavior Modeling. - Hirotaka Sakai (ER, 1983)

Entity-Relationship Approach to Logical Database Design. - Hirotaka Sakai (ER, 1983)

A Method for Behavior Modeling in Data Oriented Approach to System Design. - Hirotaka Sakai; Hajime Horiuchi (ICDE, 1984)

Entity-relationship behavior modeling in conceptual schema design. - Hirotaka Sakai (J. Syst. Softw., 1984)

An Object Behavior Modeling Method. - Hirotaka Sakai (DEXA, 1990)

An Object Behavior Modeling Augmented with Modeling Integrity Constraints. - Hirotaka Sakai (DASFAA, 1991)