APA (7th ed.) Citation

Casson, H. N. (1997). The History of the Telephone. Project Gutenberg.

Chicago Style (17th ed.) Citation

Casson, Herbert Newton. The History of the Telephone. Project Gutenberg, 1997.

MLA (9th ed.) Citation

Casson, Herbert Newton. The History of the Telephone. Project Gutenberg, 1997.

Warning: These citations may not always be 100% accurate.