APA (7th ed.) Citation

Chamberlain, L., & Pfeifer, H. (2008). The Other Side of the Door. Project Gutenberg.

Chicago Style (17th ed.) Citation

Chamberlain, Lucia, and Herman Pfeifer. The Other Side of the Door. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Chamberlain, Lucia, and Herman Pfeifer. The Other Side of the Door. Project Gutenberg, 2008.

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