Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "ealning." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 23.
.Add :-- Ðú wuldres God ealning ábidde þ̵ hé þé ne forlǽte láðum tó handum, Dóm. L. 30, 28. Alning (ealling, v. l.), Gr. D. 146, 8: 290, 14: 324, 11. v. ealling.