Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "á-cumba." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 755.
, an; m: ǽ-cumbe, an; n ? [cemban to comb]. I.oakum, that which is combed, the coarse part of hemp,--Hards, flax, tow; stuppa = στύππη,στύπη [v. heordas stuppæ, R. 68] :-- Afyl ða wúnde, and mid ácum-ban besweð fill the wound, and swathe up with tow. L. M. 1, 1; Lchdm, ii. 22, 21. Ǽcumbe stuppa, Ælfc. Gl. 64; Som. 69, 2; Wrt. Voc. 40, 36.