Appropriation

I have read a few of the books and noted that some artist have used music and inernet in their work.
Through looking into will o' the wisps in my studio work i discovered that Franz Liszt's song "feux Follets" is about will o the wisps.
as is "Cancion del fuego fatuo" in Manuel de Fallas ballet " El amor brujo. I could edit these songs to save making my own up, which would be time consuming. This was, appropriation may be covered