Country, external ennumeration?

Hi, on this schema.org
blogpost<http://blog.schema.org/2012/05/schemaorg-markup-for-external-lists.html>
I
read the follwing:

Each schema.org type (such as Person <http://schema.org/Person>,
> PostalAddress <http://schema.org/PostalAddress>) is associated with a set
> of properties, such as
> "nationality", "addressCountry". In turn, each property has one or more
> expected types; in this case, both the "nationality" of a Person, and the
> "addressCountry" of a PostalAddress <http://schema.org/PostalAddress> expect
> to have a Country <http://schema.org/Country>value


So I took a look at the example in the same blogpost, and the specify the
country like this:

<link itemprop="nationality" href="http://en.wikipedia.org/wiki/United_States"/>

When I read this blogpost
<http://blog.schema.org/2012/11/good-relations-and-schemaorg.html>
about Schema.org and Goodrelations, this is explained like:


  general approach for referencing 'external
enumerations<http://blog.schema.org/2012/05/schemaorg-markup-for-external-lists.html>
> '.


However, when I look at the itemtype 'Country' <http://schema.org/Country>,
which is the expected type for the item properties 'nationality' and
'addressCountry', I don't see anything explaining the above...

It only tells me:

A country


I do see a list of properties, but the best option there is to use 'name'
from 'Thing', which in that case should be 'text' just putting down the
name of the country. Nobody is explaining me that I have to link to, for
example, WikiPedia as explained in the blogpost.

So, what's the best practise here?

And why is 'Country' not a more specif type of Enumeration,
http://schema.org/Enumeration,

Kind regards,

Willem