Bulla, C. R., & Otani, J. (1994). What makes a shadow? (Rev. ed.). HarperCollins.
Cita Chicago Style (17a ed.)Bulla, Clyde Robert, y June Otani. What Makes a Shadow? Rev. ed. New York, NY: HarperCollins, 1994.
Cita MLA (8a ed.)Bulla, Clyde Robert, y June Otani. What Makes a Shadow? Rev. ed. HarperCollins, 1994.
Precaución: Estas citas no son 100% exactas.