APA (7th ed.) Citation

Ostwald, W., & Seltzer, T. (2013). Natural Philosophy. Project Gutenberg.

Chicago Style (17th ed.) Citation

Ostwald, Wilhelm, and Thomas Seltzer. Natural Philosophy. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Ostwald, Wilhelm, and Thomas Seltzer. Natural Philosophy. Project Gutenberg, 2013.

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