Cita APA

Ullman, J. D., & Widom, J. (1997). A first course in database systems. Prentice Hall.

Citación estilo Chicago

Ullman, Jeffrey D., and Jennifer Widom. A First Course in Database Systems. Upper Saddle River, N.J.: Prentice Hall, 1997.

Cita MLA

Ullman, Jeffrey D., and Jennifer Widom. A First Course in Database Systems. Prentice Hall, 1997.