APA (7th ed.) Citation

Lehnert, J. (1974). Introduction to telegraph engineering (2. ed.). Siemens.

Chicago Style (17th ed.) Citation

Lehnert, Josef. Introduction to Telegraph Engineering. 2. ed. Berlin ; München: Siemens, 1974.

MLA (9th ed.) Citation

Lehnert, Josef. Introduction to Telegraph Engineering. 2. ed. Siemens, 1974.