APA (7th ed.) Citation

Yeats, W. B. (2004). Four Years. Project Gutenberg.

Chicago Style (17th ed.) Citation

Yeats, W. B. Four Years. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Yeats, W. B. Four Years. Project Gutenberg, 2004.

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