APA (7th ed.) Citation

Riis, J. A. (2006). Nibsy's Christmas. Project Gutenberg.

Chicago Style (17th ed.) Citation

Riis, Jacob A. Nibsy's Christmas. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Riis, Jacob A. Nibsy's Christmas. Project Gutenberg, 2006.

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