I've recently found a very nice survey paper called "Notions of Computability at Higher Type" by John R. Longley.
The paper says it is part of a 3-part series, with the 3rd concerning non-extensional notions of computability, corresponding to computability in languages with effects.
This part might be relevant to my own research so I'm very interested in finding it. However, I can't find a version of part III anywhere. Was it ever completed? If not is there another good resource on the subject you would recommend?