If you haven't already I highly recommend reading "Introduction to Cybernetics" by Ashby, it's got the nitty-gritty formalization that later "Second Generation" et. al. cybernetics drifted away from.
> This publication has been made possible largely through Mick Ashby, the author's grandson, who has convinced the copyright holders (the Ashby estate) that they should allow us to produce an electronic version.
You can get a free PDF of the book here: http://pcp.vub.ac.be/ASHBBOOK.html
> This publication has been made possible largely through Mick Ashby, the author's grandson, who has convinced the copyright holders (the Ashby estate) that they should allow us to produce an electronic version.