Sarah Courtauld. (2019). "Frogs (First Reading Level 3) [Paperback] [Jan 01, 2010] NILL". Usborne.
Cita Chicago (17th ed.)Sarah Courtauld. "Frogs (First Reading Level 3) [Paperback] [Jan 01, 2010] NILL". Usborne, 2019.
Cita MLA (9th ed.)Sarah Courtauld. "Frogs (First Reading Level 3) [Paperback] [Jan 01, 2010] NILL". Usborne, 2019.
Atenció: Aquestes cites poden no estar 100% correctes.