APA引文

Hettwig, E. (1963). Direct distance dialing. Siemens.

Chicago Style (17th ed.) Citation

Hettwig, Emanuel. Direct Distance Dialing. Germany: Siemens, 1963.

MLA引文

Hettwig, Emanuel. Direct Distance Dialing. Siemens, 1963.

警告：這些引文格式不一定是100％准確.