Held, G. (1994). Understanding data communications (4th ed.). Sams Pub.
芝加哥风格引文Held, Gilbert. Understanding Data Communications. 4th ed. Carmel, Ind: Sams Pub, 1994.
MLA引文Held, Gilbert. Understanding Data Communications. 4th ed. Sams Pub, 1994.
警告：这些引文格式不一定是100％准确.