APA (7th ed.) Citation

Leighton, J. (2007). The Royal Picture Alphabet. Project Gutenberg.

Chicago Style (17th ed.) Citation

Leighton, John. The Royal Picture Alphabet. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Leighton, John. The Royal Picture Alphabet. Project Gutenberg, 2007.

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