Why can't references to (allegedly) biased source be references? Every author has an agenda, knowingly or unknowingly. Unless they referenced papers are false or lie they still may reference facts that allow you to form your own opinion - just don't take every conclusion at face value. At least the author provides you with the references so you can go an check for yourself.

Also: Why are you excluding reference 1? It's a paper written for the RICS, which is an institution of the royal charter. They probably have their own agenda, but I'd not expect them to publish false information.

There's nothing wrong with an article referencing something from another article in the same paper. It doesn't count as a circular reference if the articles are by separate, identifiable authors. Wikipedia needs stricter citation rules because it's harder to verify authorship.