Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Axiom of union:

This text has been unreferenced on Wikipedia for a very long time. If you can't find a source, be bold and remove it!

"

However, in its full generality, the axiom of union is independent from the rest of the ZFC-axioms:[citation needed] Replacement does not prove the existence of the union of a set of sets if the result contains an unbounded number of cardinalities.