Astley, N. a. B. (2003). Peppa Pig: Best Friends. Penguin Random House Children.
Lua i Stíl Chicago (17ú heag.)Astley, Neville and Baker. Peppa Pig: Best Friends. United Kingdom: Penguin Random House Children, 2003.
Lua MLA (8ú heag.)Astley, Neville and Baker. Peppa Pig: Best Friends. Penguin Random House Children, 2003.
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