Linked from
The 47 pages that link to Zermelo–Fraenkel set theory, each with the reason it gives.
SetRelated: Its axioms replace unrestricted collection-building with controlled principles.
ParadoxRelated: Its axioms avoid the unrestricted set formation that produces Russell's paradox.
Axiom of extensionalityRelated: Extensionality is one of its standard axioms.
Von Neumann universeRelated: Its axioms describe and constrain the sets in the hierarchy.