Colliding Worlds 1: Jedket's Harp
Jedket's Harp is one example. In a work in progress, Jordana Dane is a singer who also plays the harp. One of the solo pieces she does at a festival is called Jedket's Harp. In a story called Lilly of Mirryam, young Lilliandra has a friend named Jedket, who shows her the rare crystal formation called an elf harp.
So, Jordy must have read Lilly of Mirryam...
Probably not one reader in five hundred would have picked up that allusion. But now you know!