Start with Why robots will have emotions, in International Joint Conference on AI 7 (1981). There's a photocopy of this in Psychology.
Most of the rest of the reading is from the journal Cognition and Emotion (RSL Psychology, open shelves). Start with the article by Johnson-Laird in number 1, volume 1 of the journal. It is, I think, the first time these ideas were published in their present form, though Sloman's earlier article makes some of these points, and Simon's book The Science of the Artificial contributed some ideas.
Johnson-Laird's article is followed by a criticism from Aaron Sloman. Read that as well. (You may find that these two are unavailable because the journal is being bound. If so, sorry. I've put copies of some of the other references in Psychology.)
The first article refers to the Hacker planning program, and the difference between ``careful'' and ``careless'' modes. Look these up in AI and Natural Man.
You will find the same topics further developed in volume 1 number 3 of Cognition and Emotion. Read the editorial and Sloman's article; and at least skim Frijda's article. There are photocopies of Sloman's and Frijda's articles in Psychology.
Do you think Frijda's program is in any sense a cognitive model? Does it actually have emotions? Or it it just a superficial simulation of behaviour?