Boynton, S. (1990). Hippos go berserk. Mammoth.
Cita Chicago (17th ed.)Boynton, Sandra. Hippos Go Berserk. [Lieu d'édition inconnu]: Mammoth, 1990.
Cita MLA (8th ed.)Boynton, Sandra. Hippos Go Berserk. Mammoth, 1990.
Atenció: Aquestes cites poden no estar 100% correctes.