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:
- Is the claim attached to a named source (Citation)?
- Do citations hyperlink to source content (Can you find the source online)?
- Is the person being quoted a reliable source for this information (Knows a lot about it)?
- Was the quote taken out of context (Read the source a little)?
- Where else was that quote used (Google a snippet)?