Descriptors
===========
Descriptors describe Newsarticles found on the Web.
They may be referenced by associationindexes and
provide any metainformation (except associations)
about a Newsarticle.

A descriptor consist of:

Title		: 	The articles Title
Publicationdate	: 	The publicationdate as described in the document 
			about timemodelling.
Mirror		:	A (relative) URL that points to the location of
			a copy of the article made just after the 
			instantiation of this descriptor
Origin		:	The Name of the onlinesource and a URL to the
			location of the article on the WEB (may be 
			outdated due to the nature of the onlinesource,
			therefore the Mirror)
Comment		:	Any comment (maybe also a list of informal
			keywords as described below)


informal keywords
----------------- 
Informal keywords may be used in the comment to describe the content of 
the article. They are a kommaseparated list of words (or phrases) started 
by "KW:" and endet by a period.
