APA (7th ed.) Citation

Yardley, H. O. (1940). Secret service in America: The American Black Chamber (1. publ.). Faber & Faber.

Chicago Style (17th ed.) Citation

Yardley, Herbert O. Secret Service in America: The American Black Chamber. 1. publ. London: Faber & Faber, 1940.

MLA (9th ed.) Citation

Yardley, Herbert O. Secret Service in America: The American Black Chamber. 1. publ. Faber & Faber, 1940.