Shapp, M., & Shapp, C. (1961). Let's find out what's in the sky. Franklin Watts.
Citazione stile Chigago Style (17a edizione)Shapp, Martha, e C. Shapp. Let's Find Out What's in the Sky. New York: Franklin Watts, 1961.
Citatione MLA (9a ed.)Shapp, Martha, e C. Shapp. Let's Find Out What's in the Sky. Franklin Watts, 1961.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.