APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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