APA (7th ed.) Citation

Fiske, J. (2008). The Critical Period of American History. Project Gutenberg.

Chicago Style (17th ed.) Citation

Fiske, John. The Critical Period of American History. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Fiske, John. The Critical Period of American History. Project Gutenberg, 2008.

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