How much memory does a reference take up?

If you ignore all the extra memory overhead involved in storing variables (such as keeping track of property names etc)…

How many bytes does Flash use to store a single reference to a “complex object”?

And a related question (to avoid creating two threads):
How many bytes does a String take up?
[size=1]I’m guessing one byte per character, plus an extra byte for the “end of string” character?[/size]