Cita APA (7a ed.)

Helmer, W., & Bilek, A. J. (2004). The St. Valentine's Day massacre: The untold story of the gangland bloodbath that brought down Al Capone. Cumberland House.

Cita Chicago Style (17a ed.)

Helmer, William, y Arthur J. Bilek. The St. Valentine's Day Massacre: The Untold Story of the Gangland Bloodbath That Brought Down Al Capone. Nashville, Tenn: Cumberland House, 2004.

Cita MLA (8a ed.)

Helmer, William, y Arthur J. Bilek. The St. Valentine's Day Massacre: The Untold Story of the Gangland Bloodbath That Brought Down Al Capone. Cumberland House, 2004.