Kathleen Weidner Zoehfeld. (2012). National Geographic Readers: Rocks and Minerals (39197th.). National Geographic Children's Books.
Cita Chicago (17th ed.)Kathleen Weidner Zoehfeld. National Geographic Readers: Rocks and Minerals. 39197th. National Geographic Children's Books, 2012.
Cita MLA (9th ed.)Kathleen Weidner Zoehfeld. National Geographic Readers: Rocks and Minerals. 39197th. National Geographic Children's Books, 2012.
Atenció: Aquestes cites poden no estar 100% correctes.