Ullman, J. D., & Widom, J. (1997). A First course in database systems.
Chicago Edition CitationUllman, Jeffrey D., i Jennifer Widom. A First Course in Database Systems. New Jersey, Prentice-Hall, 1997.
Cita MLAUllman, Jeffrey D., i Jennifer Widom. A First Course in Database Systems. 1997.
Atenció: Aquestes cites poden no estar 100% correctes.