Lock, D. (2011). Emperor penguins (1st American ed.). DK Publishing.
Cita Chicago Style (17a ed.)Lock, Deborah. Emperor Penguins. 1st American ed. New York, N.Y.: DK Publishing, 2011.
Cita MLA (8a ed.)Lock, Deborah. Emperor Penguins. 1st American ed. DK Publishing, 2011.
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