Cita APA (7th ed.)

Codd, E. F. (1990). The relational model for database management: Version 2. Addison-Wesley.

Cita Chicago (17th ed.)

Codd, E. F. The Relational Model for Database Management: Version 2. Reading: Addison-Wesley, 1990.

Cita MLA (9th ed.)

Codd, E. F. The Relational Model for Database Management: Version 2. Addison-Wesley, 1990.