Cite the scanned version of the original dicionary like this:
Bosworth, Joseph. "eald-dagas." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth. Ed. Thomas Northcote Toller. Oxford: Clarendon Press, 1898. 227.
.Add :-- Be ðám ðe hit of ealddagum witan gerǽddan, Angl. ix. 259, 6. þ̵ hié gemunden þára ealdena treówa ... þe hié hæfdon ... ǽr on ealddagum, Ors. 2, 5; S. 82, 20. On ealddagum wæs án hús árǽred Gode tó lofe binnan þǽre byrig Gerusalem, Wlfst. 277, 13.