APA (7th ed.) Citation

Lee, G. S. (2007). The Voice of the Machines An Introduction to the Twentieth Century. Project Gutenberg.

Chicago Style (17th ed.) Citation

Lee, Gerald Stanley. The Voice of the Machines An Introduction to the Twentieth Century. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Lee, Gerald Stanley. The Voice of the Machines An Introduction to the Twentieth Century. Project Gutenberg, 2007.

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