APA (7th ed.) Citation

Henderson, W. E., & McPherson, W. (2007). An Elementary Study of Chemistry. Project Gutenberg.

Chicago Style (17th ed.) Citation

Henderson, William Edwards, and William McPherson. An Elementary Study of Chemistry. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Henderson, William Edwards, and William McPherson. An Elementary Study of Chemistry. Project Gutenberg, 2007.

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