Documentation for Fake News Fitness 2.0 can be found here: docs.fakenewsfitness.org
If your article makes factual claims, these must be linked to sources if you are to consider trusting it. Articles may be reporting on only one source, but studies (not merely reporting, but also analyzing) should cite multiple sources. This is called triangulation: verifying details, facts, quotes, etc. with multiple sources.
So, ask yourself, when you are analyzing the claims made by a page: