APA (7th ed.) Citation

Del Rey, L. (2006). The Sky Is Falling. Project Gutenberg.

Chicago Style (17th ed.) Citation

Del Rey, Lester. The Sky Is Falling. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Del Rey, Lester. The Sky Is Falling. Project Gutenberg, 2006.

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