Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "teágan." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 72.
, teán; p. teáde; pp. teád To dress, prepare :-- Íserngelóman ðæt land mid tó teágenne. Ðá ðæt land ðá geteád wæs, Bd. 4, 28; S. 605, 33. Wel geteád alwe, Lchdm. ii. 226, 14, v. ge-teágan; tawian.