For example, If I say
WWI erupted in 1914 as response to the murder of Archduke Franz Ferdinand of Austria in Sarajevo
or
In 1922 the League of Nations and the british separated transJordan from the rest of the territory of palestine under the British mandate, in in 1946 the Jordan Kingdom formed on that territory.
Those are well known and undisputed facts. A wikipedia article describing these events can be linked to easily, but even then, for some basic facts Wikipedia doesn't provide a source, or doesn't provide a source in the first place where the "claim" appears. For example: In the Wiki article for the six days war the first sentence describing the Israeli territorial gain is:
Within six days, Israel had won a decisive land war. Israeli forces had taken control of the Gaza Strip and the Sinai Peninsula from Egypt, the West Bank and East Jerusalem from Jordan, and the Golan Heights from Syria.
Without sources. There may be sources later in the article to those "claims", I didn't check.
Can we source well established historical facts just by sourcing the Wikipedia page talking about the issue, or even avoid sourcing at all; Especially, if later sources assume that what is described indeed happen?