Footnotes

Chapter 1

1. E. F. Codd, "A Relational Model of Data for Large Shared Data Banks," Communications of the ACM, Vol. 13, No. 6 (June 1970).

2. Peter Pin Shan Chen, "The Entity Relationship Model—Toward a Unified View of Data?", ACM TODS 1, No. 1 (March 1976).

Chapter 4

1. C. J. Date, An Introduction to Database Systems, 6^th ed. (Reading: Addison-Wesley, 1995), 128.