[Gayalondiel]

I don't think Rowling knowingly copied any authors, but similarities come through from several books. certain parallels can be drawn between characters from LOTR and the chronicles of Narnia, and to an extent the 'Worst Witch' books as well. Realistically though, Narnia and LOTR have influenced most fantasy books written after them, and they all of the above Rowling has probably read at some stage. The ideas she's used seem to be generally ingrained in most peoples minds when they think about wizards