Jazz Research?

I have spent the last hour* or more looking for an academic article on jazz improvisation. My intension is to find an "expert" text I can compare my student texts to, but I'm struggling to find anything appropriate and so let me vent a little.

It seems that writing about jazz improvisation creates one of five text types:

1. Reviews - Reviews of live performance, reviews of recordings, but reviews nonetheless.
2. Biographies and Player profiles - whether old and established, or young and up-and-coming, there are stories recounting who the player is, how they were influenced and why they are amazing.
3. Philosophical treatises - I say philosophical but they may also be psychological, neuropsychological, behavioural or influenced by a plethora of disciplines. To be completely honest, none of them really interest me. The level of technicality is high and the specificity is narrow. 
4. Applications - whether it be using improvisation to interest low socio-economic highschool students in literature, or in treatment of attention deficit disorders, or pedagogies for teaching jazz improvisation, it's all interesting and worthwhile, but not what I'm looking for, not analysing improvisation itself.
5. Poems - I don't know why. I ticked "peer-reviewed publications only", I selected "not newspapers" and still I ended up with poems.

The missing number 6 is what I'm looking for - somebody sitting down with some music, and analysing it for interesting characteristics, innovative techniques and various structures. That research may be based on a single musician - as in the corpus I'm looking at - or it may focus on a particular characteristics across a number of musicians. But as yet, I can't find it.

This, I'm sure, will have a knock-on effect in my research. I can see it now - several pages dedicated to this issue in the context, or maybe in justifying my research. All of which will basically say: actually it's amazing these students can write as they do given there are no expert texts.

The caveat to that is, of course, that there are model texts - but model texts from other students. Where is the expert text? If academic writing merges into journalism, what effect does this have? It may explain some of the characteristics of the students texts. It certainly explains their not-so-academic references. But why should they try to write academically if it will not be useful?

I understand the purpose of the research project for the students. I understand that they build on previous assignments and previous analyses to create something larger. I understand that one ambition of the curriculum designers is to add to the body of research on jazz out there.

But then, is journalism the academia of music, with a larger, more popular and less specialised readership?

UPDATE: I found an article. Just one, but an article nonetheless. Maybe one day someone out there should do a corpus analysis of the type of documents that appear in response to a search of "jazz improvisation". 

*I wrote this a month or two ago and am only now publishing it.