Riordan, R. (2012). The Heroes of Olympus The Mark of Athena. Penguin Books Ltd.
Cita Chicago (17th ed.)Riordan, Rick. The Heroes of Olympus The Mark of Athena. Penguin Books Ltd, 2012.
Cita MLA (8th ed.)Riordan, Rick. The Heroes of Olympus The Mark of Athena. Penguin Books Ltd, 2012.
Atenció: Aquestes cites poden no estar 100% correctes.