Here are some notes I've taken the past year or so that helped me think about differences and similarities between art, music, literature, and hybrid forms, or the relationship between performance and art, or other things like that. The categories of "sensory content," "delayed sensory content," and "mimetic content" come from Elaine Scarry's Dreaming by the book.  Karl Young's work is also significant in this context; you can learn more about his work, if interested, here.