Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "folc-geréfa." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 229.
, an; m. A folk-reeve, a people's governor; pŏpŭli præpŏsĭtus :-- Folcgeréfa actionātor, Ælfc. Gl. 5; Som. 56, 25; Wrt. Voc. 17, 30. v. Du Cange, sub voce Actionator.