APA (7th ed.) Citation

Mach, E., & McCormack, T. J. (2012). Popular scientific lectures. Project Gutenberg.

Chicago Style (17th ed.) Citation

Mach, Ernst, and Thomas J. McCormack. Popular Scientific Lectures. Project Gutenberg, 2012.

MLA (9th ed.) Citation

Mach, Ernst, and Thomas J. McCormack. Popular Scientific Lectures. Project Gutenberg, 2012.

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