When is it a pointer (aka reference) - when is it a copy?

[Magnus Lycka]

Fredrik Lundh wrote:
> this article
> 
>     http://effbot.org/zone/python-objects.htm
> 
> may be useful for those who haven't already seen it.

I don't know how many times I've referred to, or paraphrased,
that article. Shouldn't it be incorporated into the standard
tutorial? I think it's very helpful for people who are used
to the way C etc handles variables.