Steven Clarke (a usability researcher here at Microsoft) has published a set of very interesting papers discussing the core concepts of framework usability.
I thought I'd collect them for your reading pleasure...
1. Dr. Dobbs article on Measuring Api Usability which introduce our approach to measuring API usability. (Updated link from original post ).
2. The Journal of Visual Languages and Computing (volume 17 issue number 4) has an article on the Cognitive Dimensions framework that includes a section on how we apply the framework and the personas at Microsoft.
3. A short paper presented recently at a workshop in Germany on End User Programming. The paper is a briefly describe the three developer personas we design for. [Associated slide deck]
4. A paper from the Cognitive Dimensions workshop at the IEEE conference on Visual Languages in 2005. It gives a very simple and brief overview of how we profile personas using the framework but doesn’t describe the personas in detail.