APA (7th ed.) Citation

Newton, I. (2009). Philosophiae naturalis principia mathematica by Sir Isaac Newton. Project Gutenberg Literary Archive Foundation.

Chicago Style (17th ed.) Citation

Newton, Isaac. Philosophiae Naturalis Principia Mathematica by Sir Isaac Newton. Salt Lake City: Project Gutenberg Literary Archive Foundation, 2009.

MLA (9th ed.) Citation

Newton, Isaac. Philosophiae Naturalis Principia Mathematica by Sir Isaac Newton. Project Gutenberg Literary Archive Foundation, 2009.

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