  Every AF-algebra arises as a graph algebra in the sense of Kumjian, Pask,
Raeburn, and Renault. For AF-algebras, the diagonal subalgebra defined by
Stratila and Voiculescu is consistent with Kumjian's notion of diagonal, and
the groupoid arising from a well-chosen Bratteli diagram for A coincides with
Kumjian's twist groupoid constructed from a diagonal of A.
