The Original Reporting Source (ORS) will give you the most trustworthy information. Always search for the source that originally created the information.
Teachers have been telling you for years that Wikipedia is not a valid source but that is not always true. As a fact checker, Wikipedia is an ally and your first line of defense for authenticating and verifying alleged-facts.
The person/people that produced the original writing are the ones that verified the facts in the first place. They are the Original Reporting Source (ORS). If we find that the ORS is valid, we can invest our time into the article. When we seek out the ORS, we are searching "upstream."