APA (7th ed.) Citation

Cox, G. (2011). The International Auxiliary Language Esperanto Grammar and Commentary. Project Gutenberg.

Chicago Style (17th ed.) Citation

Cox, George. The International Auxiliary Language Esperanto Grammar and Commentary. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Cox, George. The International Auxiliary Language Esperanto Grammar and Commentary. Project Gutenberg, 2011.

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