Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "deófol." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 761.
, deóful, dióful; contracted to deófl; gen. es; dat. e; nom. pl. deóflu, deófol; gen. deófla; m. n. The DEVIL; diabŏlus. I.m. Nú þencþ menig man and smeáþ hwanon deófol cóme? Ðonne wite he ðæt God gesceóp, to mǽran engle, ðone ðe nú is deófol; ac God ne gesceóp hine ná to deófle; ac ðá ðá he wæs mid ealle fordón and forscyldgod þurh ða miclan upahefednysse and wiðerweardnysse, ðá wearþ he to deófle awend, se ðe ǽr wæs mǽre engel geworht now many a man will think and inquire whence the devil came?