APA (7th ed.) Citation

Baring-Gould, S. (2005). Cliff Castles and Cave Dwellings of Europe. Project Gutenberg.

Chicago Style (17th ed.) Citation

Baring-Gould, S. Cliff Castles and Cave Dwellings of Europe. Project Gutenberg, 2005.

MLA (9th ed.) Citation

Baring-Gould, S. Cliff Castles and Cave Dwellings of Europe. Project Gutenberg, 2005.

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