Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "fág." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 763.
, fáh; def. se fága, seó, ðæt fáge; adj. Coloured, stained, dyed, tinged, shining, variegated; tinctus, cŏlōrātus, vărius, versicŏlor, discŏlor :-- Wæter wældreóre fág water stained with deadly gore, Beo. Th. 3267; B. 1631. Ðæt sweord fáh and fæted the sword blood-stained and ornate, 5395; B. 2701: 2576; B. 1286. Bleóbrygdum fág shining with variegated colours, Exon. 60 a; Th. 218, 9; Ph. 292. Gár golde fáh a weapon shining with gold, Menol. Fox 503; Gn. C. 22. Fýrmǽlum fág variegated with marks of fire, Andr. Kmbl. 2269; An. 1136.