APA (7th ed.) Citation

Yeats, W. B. (2010). The Wild Swans at Coole. Project Gutenberg.

Chicago Style (17th ed.) Citation

Yeats, W. B. The Wild Swans at Coole. Project Gutenberg, 2010.

MLA (9th ed.) Citation

Yeats, W. B. The Wild Swans at Coole. Project Gutenberg, 2010.

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