We have the following indirect implication of form equivalence classes:
			
| Implication | Reference | 
|---|---|
| 66 \(\Rightarrow\) 67 | Existence of a basis implies the axiom of choice, Blass,  A. 1984a, Contemporary Mathematics | 
| 67 \(\Rightarrow\) 232 | Paracompactness of metric spaces and the axiom of choice, Howard,  P. 2000a, Math. Logic Quart. | 
Here are the links and statements of the form equivalence classes referenced above:
| Howard-Rubin Number | Statement | 
|---|---|
| 66: | Every vector space over a field has a basis. | 
| 67: | \(MC(\infty,\infty)\) \((MC)\), The Axiom of Multiple Choice: For every set \(M\) of non-empty sets there is a function \(f\) such that \((\forall x\in M)(\emptyset\neq f(x)\subseteq x\) and \(f(x)\) is finite). | 
| 232: | Every metric space \((X,d)\) has a \(\sigma\)-point finite base. | 
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