Cita APA (7a ed.)

Ullman, J. D. (1989). Principles of database and knowledge-base systems. [S.n.].

Cita Chicago Style (17a ed.)

Ullman, Jeffrey D. Principles of Database and Knowledge-base Systems. Rockville: [S.n.], 1989.

Cita MLA (9a ed.)

Ullman, Jeffrey D. Principles of Database and Knowledge-base Systems. [S.n.], 1989.