APA (7th ed.) Citation

Andersen, H. C. (1990). The ugly duckling. Project Gutenberg.

Chicago Style (17th ed.) Citation

Andersen, Hans Christian. The Ugly Duckling. Champaign, Ill: Project Gutenberg, 1990.

MLA (9th ed.) Citation

Andersen, Hans Christian. The Ugly Duckling. Project Gutenberg, 1990.

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