Jackie Gaff. (2003). Stalactites Hang Down: And Other Questions About Caves (I Wonder Why) (I Wonder Why Series). Kingfisher Books.
Chicago-viite (17. p.)Jackie Gaff. Stalactites Hang Down: And Other Questions About Caves (I Wonder Why) (I Wonder Why Series). Kingfisher Books, 2003.
MLA-viite (9. p.)Jackie Gaff. Stalactites Hang Down: And Other Questions About Caves (I Wonder Why) (I Wonder Why Series). Kingfisher Books, 2003.
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