APA (7th ed.) Citation

Doyle, A. C. (2004). The Firm of Girdlestone. Project Gutenberg.

Chicago Style (17th ed.) Citation

Doyle, Arthur Conan. The Firm of Girdlestone. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Doyle, Arthur Conan. The Firm of Girdlestone. Project Gutenberg, 2004.

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