I think Henry Baker had a paper on why generational and refcounting GCs are ultimately equivalent. Couldn't find it quickly, though, to give you a link.
I think you might be thinking of this paper: A unified theory of garbage collection [1], which shows how most modern collectors are hybrids of GC and ref counting.
For the record: This is a very good paper. It's extremely easy to read, even for somebody who knows nothing about the background, and the scientific result is absolutely beautiful!
I just wanted to say thank you for this comment. I'm reading the paper because of it. Can you please point me to your other favorites that are good + accessible?
[1] http://atlas.cs.virginia.edu/~weimer/2008-415/reading/bacon-...