APA (7th ed.) Citation

Huxley, T. H. (2001). Geological Contemporaneity and Persistent Types of Life. Project Gutenberg.

Chicago Style (17th ed.) Citation

Huxley, Thomas Henry. Geological Contemporaneity and Persistent Types of Life. Project Gutenberg, 2001.

MLA (9th ed.) Citation

Huxley, Thomas Henry. Geological Contemporaneity and Persistent Types of Life. Project Gutenberg, 2001.

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