APA (7th ed.) Citation

Gay, J. (2000). The Beggar's Opera. Project Gutenberg.

Chicago Style (17th ed.) Citation

Gay, John. The Beggar's Opera. Project Gutenberg, 2000.

MLA (9th ed.) Citation

Gay, John. The Beggar's Opera. Project Gutenberg, 2000.

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