APA (7th ed.) Citation

Childers, E. (2011). The riddle of the sands: A record of secret service. Penguin Books.

Chicago Style (17th ed.) Citation

Childers, Erskine. The Riddle of the Sands: A Record of Secret Service. New York: Penguin Books, 2011.

MLA (8th ed.) Citation

Childers, Erskine. The Riddle of the Sands: A Record of Secret Service. Penguin Books, 2011.

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