Cita APA (7th ed.)

Held, G. (1994). Understanding data communications (4th ed.). Sams Pub.

Cita Chicago (17th ed.)

Held, Gilbert. Understanding Data Communications. 4th ed. Carmel, Ind: Sams Pub, 1994.

Cita MLA (9th ed.)

Held, Gilbert. Understanding Data Communications. 4th ed. Sams Pub, 1994.