APA (7th ed.) Citation

Sowerby, G. B. (2013). Illustrated Index of British Shells Containing figures of all the recent species. Project Gutenberg.

Chicago Style (17th ed.) Citation

Sowerby, George Brettingham. Illustrated Index of British Shells Containing Figures of All the Recent Species. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Sowerby, George Brettingham. Illustrated Index of British Shells Containing Figures of All the Recent Species. Project Gutenberg, 2013.

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