Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "þancian." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 727.
;p. ode. I.to thank, give thanks, express in words or have in mind feelings of gratitude, (1) absolute :-- Drihten ðancode, ǽrðan ðe hé ða hláfas tóbrǽce, Homl. Th. ii. 400, 16. Hé genam ðone calic þanciende accipiens calicem gratias egit, Mt. Kmbl. 26, 27. (2) with dat. of person to whom thanks are given :-- Ðé þanciaþ Cristes þegnas, Hy. 7, 52, 49. Hí tó ðé cleopiaþ and ðé lofe þanciaþ clamabunt et hymnum dicent, Ps. Th. 64, 14. Hé Gode þancode, Mk. Skt. 8, 6: Homl. Skt. i. 3, 454.