I was introducing corporate communications yesterday by looking at stakeholders and by looking at PR functions. A conceptualised map came into my head and I scribbled it on the whiteboard (see image, please enlarge for detail).
It’s simplified of course, but not I hope too simplistic. One student asked for a reference to the source so I had to admit it was no more academic and authorised than me jotting on a whiteboard. So here it is: published of sorts, and peer reviewed of sorts (by you).
PR Studies 
I like this for its succinctness. It is a good starting point for discussing the complexity behind the labels. Not sure about the media being placed in the middle, though!